ARC: unbork 5.11 bootup: fix snafu in _TIF_NOTIFY_SIGNAL handling

Linux 5.11.rcX was failing to boot on ARC HSDK board. Turns out we have
a couple of issues, this being the first one, and I'm to blame as I
didn't pay attention during review.

TIF_NOTIFY_SIGNAL support requires checking multiple TIF_* bits in
kernel return code path. Old code only needed to check a single bit so
BBIT0 <TIF_SIGPENDING> worked. New code needs to check multiple bits so
AND <bit-mask> instruction. So needs to use bit mask variant _TIF_SIGPENDING

Cc: Jens Axboe <[email protected]>
Fixes: 53855e1 ("arc: add support for TIF_NOTIFY_SIGNAL")
Link: foss-for-synopsys-dwc-arc-processors#34
Signed-off-by: Vineet Gupta <[email protected]>

Author: vineetgarc

arch/arc/kernel/entry.S

@@ -307,7 +307,7 @@ resume_user_mode_begin:
 	mov r0, sp	; pt_regs for arg to do_signal()/do_notify_resume()
 
 	GET_CURR_THR_INFO_FLAGS   r9
-	and.f  0,  r9, TIF_SIGPENDING|TIF_NOTIFY_SIGNAL
+	and.f  0,  r9, _TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL
 	bz .Lchk_notify_resume
 
 	; Normal Trap/IRQ entry only saves Scratch (caller-saved) regs