m68k: math-emu: Add missing prototypes

When building with W=1:

    arch/m68k/math-emu/fp_arith.c:301:16: warning: no previous prototype for ‘fp_fsglmul’ [-Wmissing-prototypes]
      301 | struct fp_ext *fp_fsglmul(struct fp_ext *dest, struct fp_ext *src)
	  |                ^~~~~~~~~~
    arch/m68k/math-emu/fp_arith.c:357:16: warning: no previous prototype for ‘fp_fsgldiv’ [-Wmissing-prototypes]
      357 | struct fp_ext *fp_fsgldiv(struct fp_ext *dest, struct fp_ext *src)
	  |                ^~~~~~~~~~
      CC      arch/m68k/math-emu/fp_log.o
    ...

Fix this by adding the missing prototypes to header files.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20230810141947.1236730-17-arnd@kernel.org/Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/96c039640d76973ea762d79018de0bc75bbdc1dc.1692283195.git.geert@linux-m68k.org

arch/m68k/math-emu/fp_arith.h

@@ -26,6 +26,8 @@ struct fp_ext *fp_fcmp(struct fp_ext *dest, struct fp_ext *src);
 struct fp_ext *fp_ftst(struct fp_ext *dest, struct fp_ext *src);
 struct fp_ext *fp_fmul(struct fp_ext *dest, struct fp_ext *src);
 struct fp_ext *fp_fdiv(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsglmul(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsgldiv(struct fp_ext *dest, struct fp_ext *src);
 
 /* ones that do rounding and integer conversions */
 struct fp_ext *fp_fmod(struct fp_ext *dest, struct fp_ext *src);

arch/m68k/math-emu/fp_log.c

@@ -17,6 +17,7 @@
 
 #include "fp_arith.h"
 #include "fp_emu.h"
+#include "fp_log.h"
 
 static const struct fp_ext fp_one = {
 	.exp = 0x3fff,

arch/m68k/math-emu/fp_log.h

+/*
+
+  fp_log.h: floating-point math routines for the Linux-m68k
+  floating point emulator.
+
+  Copyright (c) 1998-1999 David Huggins-Daines / Roman Zippel.
+
+  I hereby give permission, free of charge, to copy, modify, and
+  redistribute this software, in source or binary form, provided that
+  the above copyright notice and the following disclaimer are included
+  in all such copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS", WITH ABSOLUTELY NO WARRANTY, REAL
+  OR IMPLIED.
+
+*/
+
+#ifndef _FP_LOG_H
+#define _FP_LOG_H
+
+#include "fp_emu.h"
+
+/* floating point logarithmic instructions:
+
+   the arguments to these are in the "internal" extended format, that
+   is, an "exploded" version of the 96-bit extended fp format used by
+   the 68881.
+
+   they return a status code, which should end up in %d0, if all goes
+   well.  */
+
+struct fp_ext *fp_fsqrt(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fetoxm1(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fetox(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_ftwotox(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_ftentox(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_flogn(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_flognp1(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_flog10(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_flog2(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fgetexp(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fgetman(struct fp_ext *dest, struct fp_ext *src);
+
+#endif /* _FP_LOG_H */

arch/m68k/math-emu/fp_trig.h

@@ -29,4 +29,23 @@
    they return a status code, which should end up in %d0, if all goes
    well.  */
 
+struct fp_ext *fp_fsin(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fcos(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_ftan(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fasin(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_facos(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fatan(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsinh(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fcosh(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_ftanh(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fatanh(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsincos0(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsincos1(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsincos2(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsincos3(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsincos4(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsincos5(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsincos6(struct fp_ext *dest, struct fp_ext *src);
+struct fp_ext *fp_fsincos7(struct fp_ext *dest, struct fp_ext *src);
+
 #endif /* _FP_TRIG_H */