m68k: add TIF_NOTIFY_RESUME and handle it.

TIF_NOTIFY_RESUME added (as bit 5).  That way nommu glue needs no changes at
all; mmu one needs just to replace jmi do_signal_return to jne do_signal_return
There we have flags shifted up, until bit 6 (SIGPENDING) is in MSBit; instead
of checking that MSBit is set (jmi) we check that MSBit or something below it
is set (jne); bits 0..4 are never set, so that's precisely "bit 6 or bit 5 is
set".

Usual handling of NOTIFY_RESUME/SIGPENDING is done in do_notify_resume(); glue
calls it instead of do_signal().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/m68k/kernel/entry_mm.S b/arch/m68k/kernel/entry_mm.S
index 675a854..f29e73c 100644
--- a/arch/m68k/kernel/entry_mm.S
+++ b/arch/m68k/kernel/entry_mm.S
@@ -148,7 +148,7 @@
 	jcs	do_trace_exit
 	jmi	do_delayed_trace
 	lslw	#8,%d0
-	jmi	do_signal_return
+	jne	do_signal_return
 	pea	resume_userspace
 	jra	schedule
 
@@ -172,7 +172,7 @@
 	| save top of frame
 	movel	%sp,%curptr@(TASK_THREAD+THREAD_ESP0)
 	lslb	#1,%d0
-	jmi	do_signal_return
+	jne	do_signal_return
 	pea	resume_userspace
 	jra	schedule
 
@@ -182,7 +182,7 @@
 	subql	#4,%sp			| dummy return address
 	SAVE_SWITCH_STACK
 	pea	%sp@(SWITCH_STACK_SIZE)
-	bsrl	do_signal
+	bsrl	do_notify_resume
 	addql	#4,%sp
 	RESTORE_SWITCH_STACK
 	addql	#4,%sp