[SCSI] qla2xxx: Explicitly tear-down vports during PCI remove_one().

[SCSI] qla2xxx: Explicitly tear-down vports during PCI remove_one().

During internal testing, we've seen issues (hangs) with the
'deferred' vport tear-down-processing typically accompanied with
the fc_remove_host() call.  This is due to the current
implementation's back-end vport handling being performed by the
physical-HA's DPC thread where premature shutdown could lead to
latent vport requests without a processor.

This should also address a problem reported by Gal Rosen
(http://marc.info/?l=linux-scsi&m=121731664417358&w=2) where the
driver would attempt to awaken a previously torn-down DPC thread
from interrupt context by implicitly calling wake_up_process()
rather than the driver's qla2xxx_wake_dpc() helper.  Rather, than
reshuffle the remove_one() device-removal code, during unload,
depend on the driver's timer to wake-up the DPC process, by
limiting wake-ups based on an 'unloading' flag.

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