[MIPS] Make entry.S a little more readable.

When CONFIG_PREEMPT is not set, it also moves one branch instruction from
ret_from_irq() to ret_from_exception().  Therefore we favour the return
from irq case which should be more common than the other one.
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/entry.S

@@ -21,24 +21,21 @@
 #endif
 
 #ifndef CONFIG_PREEMPT
-	.macro	preempt_stop
-	local_irq_disable
-	.endm
 #define resume_kernel	restore_all
+#else
+#define __ret_from_irq	ret_from_exception
 #endif
 
 	.text
 	.align	5
-FEXPORT(ret_from_irq)
-	LONG_S	s0, TI_REGS($28)
-#ifdef CONFIG_PREEMPT
-FEXPORT(ret_from_exception)
-#else
-	b	_ret_from_irq
+#ifndef CONFIG_PREEMPT
 FEXPORT(ret_from_exception)
-	preempt_stop
+	local_irq_disable			# preempt stop
+	b	__ret_from_irq
 #endif
-FEXPORT(_ret_from_irq)
+FEXPORT(ret_from_irq)
+	LONG_S	s0, TI_REGS($28)
+FEXPORT(__ret_from_irq)
 	LONG_L	t0, PT_STATUS(sp)		# returning to kernel mode?
 	andi	t0, t0, KU_USER
 	beqz	t0, resume_kernel