scsi: qla2xxx: Use constant when it is known

Directly return constant when it is known to make code easier to
understand.

Link: https://lore.kernel.org/r/20200921112340.GA19336@duo.ucw.cz


Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Pavel Machek (CIP) <pavel@denx.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>