[PATCH] M68k: optimize stacked irq check

M68k: optimize stacked irq check (from Roman Zippel)

arch/m68k/kernel/entry.S

@@ -246,13 +246,10 @@ ret_from_interrupt:
 2:
 	RESTORE_ALL
 1:
-#if 1
-	bfextu  %sp@(PT_SR){#5,#3},%d0	| Check for nested interrupt.
-#if MAX_NOINT_IPL > 0
-	cmpiw	#MAX_NOINT_IPL,%d0
-#endif
-	jhi	2b
-#endif
+	moveq	#(~ALLOWINT>>8)&0xff,%d0
+	andb	%sp@(PT_SR),%d0
+	jne	2b
+
 	/* check if we need to do software interrupts */
 	tstl	irq_stat+CPUSTAT_SOFTIRQ_PENDING
 	jeq	ret_from_exception