microblaze: evict the check for kernel_mode(regs) from do_notify_resume()

Only one caller hasn't done it in assembler - work_pending on !MMU.
Everything else can't reach do_notify_resume() if we are returning
to kernel mode, so move that check to that sole caller and make
do_notify_resume() reachable only when returning to userland.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/microblaze/kernel/entry-nommu.S

@@ -482,6 +482,8 @@ ENTRY(ret_from_kernel_thread)
 	addk	r3, r0, r0
 
 work_pending:
+	lwi	r11, r1, PT_MODE
+	bneid	r11, 2f
 	enable_irq
 
 	andi	r11, r19, _TIF_NEED_RESCHED
@@ -507,6 +509,7 @@ ENTRY(ret_to_user)
 no_work_pending:
 	disable_irq
 
+2:
 	/* save r31 */
 	swi	r31, r0, PER_CPU(CURRENT_SAVE)
 	/* save mode indicator */

arch/microblaze/kernel/signal.c

@@ -343,15 +343,6 @@ static void do_signal(struct pt_regs *regs, int in_syscall)
 
 asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall)
 {
-	/*
-	 * We want the common case to go fast, which
-	 * is why we may in certain cases get here from
-	 * kernel mode. Just return without doing anything
-	 * if so.
-	 */
-	if (kernel_mode(regs))
-		return;
-
 	if (test_thread_flag(TIF_SIGPENDING))
 		do_signal(regs, in_syscall);