s390/mcck: fix calculation of SIE critical section size

The size of SIE critical section is calculated wrongly
as result of a missed subtraction in commit 0b0ed65
("s390: remove critical section cleanup from entry.S")

Fixes: 0b0ed65 ("s390: remove critical section cleanup from entry.S")
Cc: <stable@vger.kernel.org>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: Alexander Gordeev

arch/s390/kernel/entry.S

@@ -651,7 +651,7 @@ ENDPROC(stack_overflow)
 .Lcleanup_sie_mcck:
 	larl	%r13,.Lsie_entry
 	slgr	%r9,%r13
-	larl	%r13,.Lsie_skip
+	lghi	%r13,.Lsie_skip - .Lsie_entry
 	clgr	%r9,%r13
 	jh	.Lcleanup_sie_int
 	oi	__LC_CPU_FLAGS+7, _CIF_MCCK_GUEST