[SCSI] qla4xxx: Fix sparse warnings

Fix following sparse warnings:-
 drivers/scsi/qla4xxx/ql4_os.c:2109:33: warning: cast truncates bits from constant value (ffff7fff becomes 7fff)
 drivers/scsi/qla4xxx/ql4_os.c:2306:33: warning: cast truncates bits from constant value (ffff7fff becomes 7fff)

Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>