[SCSI] qla2xxx: Use msleep() as delay during ISP polling.

Mailbox commands are polled for completion during ISP
initialization.  During potentially 'long' mailbox commands
(i.e. fabric login), we really don't want a busy-wait delay
to potentially trigger a (benign) soft-lockup BUG().

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>