s390/ap: fix status returned by ap_qact()

Since commit 159491f3 ("s390/ap: rework assembler functions to use
unions for in/out register variables") the  function ap_qact() tries to
grab the status from the wrong part of the register. Thus we always end
up with zeros. Which is wrong, among others, because we detect failures
via status.response_code.

Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reported-by: Harald Freudenberger <freude@linux.ibm.com>
Fixes: 159491f3 ("s390/ap: rework assembler functions to use unions for in/out register variables")
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>