s390/pkey: fix smatch warning inconsistent indenting

Fix smatch warnings:
pkey_api.c:1606 pkey_ccacipher_aes_attr_read() warn: inconsistent indenting
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>