scsi: fix operator precedence warning

Fix operator precedence warning (from sparse), which results in the
data value always being 0:

drivers/scsi/qla4xxx/ql4_mbx.c:470:66: warning: right shift by bigger than source value

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Ravi Anand <ravi.anand@qlogic.com>
Cc: David C Somayajulu <david.somayajulu@qlogic.com>
Cc: Karen Higgins <karen.higgins@qlogic.com>
Cc: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>