[S390] css: fix rsid evaluation for 2nd crw

Use correct bit positions of rsid field.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index a5050e2..825951b 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -635,7 +635,7 @@
 	init_subchannel_id(&mchk_schid);
 	mchk_schid.sch_no = crw0->rsid;
 	if (crw1)
-		mchk_schid.ssid = (crw1->rsid >> 8) & 3;
+		mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 
 	/*
 	 * Since we are always presented with IPI in the CRW, we have to