scsi: zfcp: update width in comment for ZFCP_COMMON_FLAGS mask

v2.6.10 history commit 4062e12b2ba2 ("[PATCH] s390: zfcp act enhancements")
extended this mask by one nibble with the introduction of
ZFCP_STATUS_COMMON_ACCESS_DENIED == 0x00800000 for ACT (access control
table).

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>