[POWERPC] Make setjmp/longjmp code usable outside of xmon

This makes the setjmp/longjmp code used by xmon, generically available
to other code.  It also removes the requirement for debugger hooks to
be only called on 0x300 (data storage) exception.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 10dda22..7b25107 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -167,10 +167,8 @@
 	if (notify_page_fault(regs))
 		return 0;
 
-	if (trap == 0x300) {
-		if (debugger_fault_handler(regs))
-			return 0;
-	}
+	if (unlikely(debugger_fault_handler(regs)))
+		return 0;
 
 	/* On a kernel SLB miss we can only check for a valid exception entry */
 	if (!user_mode(regs) && (address >= TASK_SIZE))