[ARM] 4531/1: remove is_in_rom() protptype

Remove unused is_in_rom() function prototype.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

include/asm-arm/pgtable-nommu.h

@@ -74,7 +74,6 @@ static inline int pte_file(pte_t pte) { return 0; }
  * These would be in other places but having them here reduces the diffs.
  */
 extern unsigned int kobjsize(const void *objp);
-extern int is_in_rom(unsigned long);
 
 /*
  * No page table caches to initialise.