s390/kvm: improve stack frame constants in entry.S

The code in sie64a uses the stack frame passed to the function to store
some temporary data in the empty1 array (see struct stack_frame in
asm/processor.h.

Replace the __SF_EMPTY+x constants with a properly defined offset:
s/__SF_EMPTY/__SF_SIE_CONTROL/, s/__SF_EMPTY+8/__SF_SIE_SAVEAREA/,
s/__SF_EMPTY+16/__SF_SIE_REASON/, s/__SF_EMPTY+24/__SF_SIE_FLAGS/.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/asm-offsets.c

@@ -63,6 +63,7 @@ int main(void)
 	OFFSET(__SF_SIE_CONTROL, stack_frame, empty1[0]);
 	OFFSET(__SF_SIE_SAVEAREA, stack_frame, empty1[1]);
 	OFFSET(__SF_SIE_REASON, stack_frame, empty1[2]);
+	OFFSET(__SF_SIE_FLAGS, stack_frame, empty1[3]);
 	BLANK();
 	/* timeval/timezone offsets for use by vdso */
 	OFFSET(__VDSO_UPD_COUNT, vdso_data, tb_update_count);