scsi: ibmvfc: Deduplicate common ibmvfc_cmd init code

The virtual FC frame command exchanged with the VIOS is used for device
reset and command abort TMF as well as normally queued commands. When
initializing the ibmvfc_cmd there are several elements of the command that
are set the same way regardless of the command type.

Deduplicate code by moving these commonally set fields into a
initialization helper routine, namely ibmvfc_init_vfc_cmd().

Link: https://lore.kernel.org/r/20201118011104.296999-2-tyreld@linux.ibm.com


Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>