powerpc: Move flush_instruction_cache() prototype in asm/cacheflush.h

flush_instruction_cache() belongs to the cache flushing function
family.

Move its prototype in asm/cacheflush.h
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/993445b5227e8ca2f0e38bcc9ea3dfea6e865920.1597384512.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/cacheflush.h

@@ -98,6 +98,8 @@ static inline void invalidate_dcache_range(unsigned long start,
 	mb();	/* sync */
 }
 
+void flush_instruction_cache(void);
+
 #include <asm-generic/cacheflush.h>
 
 #endif /* _ASM_POWERPC_CACHEFLUSH_H */

arch/powerpc/include/asm/processor.h

@@ -435,7 +435,6 @@ extern void power7_idle_type(unsigned long type);
 extern void power9_idle_type(unsigned long stop_psscr_val,
 			      unsigned long stop_psscr_mask);
 
-extern void flush_instruction_cache(void);
 extern int fix_alignment(struct pt_regs *);
 
 #ifdef CONFIG_PPC64

arch/powerpc/platforms/44x/machine_check.c

@@ -7,6 +7,7 @@
 #include <linux/ptrace.h>
 
 #include <asm/reg.h>
+#include <asm/cacheflush.h>
 
 int machine_check_440A(struct pt_regs *regs)
 {