m68k: only generate FPU instructions if CONFIG_FPU enabled

Most of the m68k code that supports a hardware FPU is surrounded by
CONFIG_FPU. Be consistent and surround the hardware FPU instruction
setup in setup_mm.c with CONFIG_FPU as well as the check for
CONFIG_M68KFPU_EMU_ONLY.

The existing classic m68k architectures all define CONFIG_FPU, so they
see no change from this. But on ColdFire where we do not support the
emulated FP code we can now compile without CONFIG_FPU being set as well.
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

arch/m68k/kernel/setup_mm.c

@@ -245,7 +245,7 @@ void __init setup_arch(char **cmdline_p)
 	 * We should really do our own FPU check at startup.
 	 * [what do we do with buggy 68LC040s? if we have problems
 	 *  with them, we should add a test to check_bugs() below] */
-#ifndef CONFIG_M68KFPU_EMU_ONLY
+#if defined(CONFIG_FPU) && !defined(CONFIG_M68KFPU_EMU_ONLY)
 	/* clear the fpu if we have one */
 	if (m68k_fputype & (FPU_68881|FPU_68882|FPU_68040|FPU_68060|FPU_COLDFIRE)) {
 		volatile int zero = 0;