[SCSI] qla2xxx: Silence bogus warning by gcc for wrap and did.

The qla2xxx driver uses a port_id_t to mark the start of its enumerations.  gcc
is complaining that wrap.b24 may be used uninitialized, but this doesn't look
to be possible.  Silence it.

Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>