Blackfin: punt duplicated search_exception_table() prototype

The common code already has a prototype for this function and we don't use
it anywhere in the Blackfin code, so punt it from the Blackfin headers.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

arch/blackfin/include/asm/uaccess.h

@@ -83,9 +83,6 @@ struct exception_table_entry {
 	unsigned long insn, fixup;
 };
 
-/* Returns 0 if exception not found and fixup otherwise.  */
-extern unsigned long search_exception_table(unsigned long);
-
 /*
  * These are the main single-value transfer routines.  They automatically
  * use the right size if we just have the right pointer type.