binfmt_flat: remove flat_reloc_valid

This helper is the same for all architectures, open code it in the only
caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

arch/microblaze/include/asm/flat.h

@@ -15,7 +15,6 @@
 
 #define	flat_argvp_envp_on_stack()	0
 #define	flat_old_ram_flag(flags)	(flags)
-#define	flat_reloc_valid(reloc, size)	((reloc) <= (size))
 #define	flat_set_persistent(relval, p)		0
 
 /*