ARC: nptl: cancellable wrappers were broken #2

ARC: nptl: cancellable wrappers were broken #2

Despite the prev fix, tst-mqueue3 was still segfaulting.
The issue was BLINK register not restored properly for return

00002690 <mq_timedsend>:
    2690:	sub	r9,r25,0x448
    2698:	ld	r10,[r9]
    269c:	cmp	r10,0
    26a0:	beq	-36
    26a4:	st.aw	blink,[sp,-4]
    26a8:	st.aw	r0,[sp,-4]
    26ac:	st.aw	r1,[sp,-4]
    26b0:	st.aw	r2,[sp,-4]
    26b4:	st.aw	r3,[sp,-4]
    26b8:	st.aw	r4,[sp,-4]
    26bc:	bl	1e28 <__librt_enable_asynccancel>
    26c0:	mov	r9,r0
    26c4:	ld.ab	r4,[sp,4]
    26c8:	ld.ab	r3,[sp,4]
    26cc:	ld.ab	r2,[sp,4]
    26d0:	ld.ab	r1,[sp,4]
    26d4:	ld.ab	r0,[sp,4]
    26d8:	ld.ab	blink,[sp, 4]   <---- function return BLINK
    26dc:	mov	r8,182
    26e0:	trap_s	0
    26e2:	cmp	r0,-1024
    26e6:	st.aw	r0,[sp,-4]
    26ea:	mov	r0,r9
    26ee:	bl	1e90 <__librt_disable_asynccancel> <-- BLINK clobbered
                                                                to next PC

    26f2:	ld.ab	r0,[sp,4]  <----|   loops here until sp is out of bound
    26fa:	cmp	r0,-1024        |
    26fe:	jls	[blink]	   -----|
    2702:	b	15d8
    2706:	nop_s

So the fix was to retain BLINK on stack before function call, and pop it
later

-   26d8:	ld.ab	blink,[sp, 4]
+   26d8:	ld	blink,[sp]      <--- restore BLINK, but retain on stack
    26dc:	mov	r8,182
    26e0:	trap_s	0
    26e2:	cmp	r0,-1024
    26e6:	st.aw	r0,[sp,-4]
    26ea:	mov	r0,r9
    26ee:	bl	1e90 <__librt_disable_asynccancel>
    26f2:	ld.ab	r0,[sp,4]
+   26f6:	ld.ab	blink,[sp,4]    <--- finally pop BLINK
    26fa:	cmp	r0,-1024
    26fe:	jls	[blink]

Reported-by: Eugeniy Paltsev <paltsev@synopsys.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>