[SCSI] libfc: Fix incorrect locking and unlocking in FCP

The error handler grabs the si->scsi_queue_lock, but
in the case where the fsp pointer is NULL it releases
the scsi_host lock. This can lead to a variety of
system hangs depending on which is used first- the
scsi_host lock or the scsi_queue_lock.

This patch simply unlocks the correct lock when fcp
is NULL.

Signed-off-by: Robert Love <robert.w.love@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>