[SCSI] qla2xxx: Correct async-srb issues.

* hold the hardware_lock throughout the duration of ctx-sp
  timeout handling -- could result in use-after-free oops.

* retry a timed-out login-request.

* done() routines are called with the hardware-lock held, issue
qla2x00_mark_device_lost() with proper 'defer' flag.

* FCP2 capabilities are only relevant to target devices.

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