s390/scm_blk: fix deadlock for requests != REQ_TYPE_FS

When we refuse a non REQ_TYPE_FS request in the build request function
we already hold the queue lock. Thus we must not call blk_end_request_all
but __blk_end_request_all.

Reported-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Fixes: de9587a2 ('s390/scm_blk: fix endless loop for requests != REQ_TYPE_FS')
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>