[SCSI] qla2xxx: Fix for build warning

drivers/scsi/qla2xxx/qla_os.c: In function 'qla2x00_probe_one':
drivers/scsi/qla2xxx/qla_os.c:1582: warning: 'mem_only' is used uninitialized in this function

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Anirban Chakraborty <anirban.chakraborty@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>