[SCSI] libfc: set seq_id for incoming sequence

After the recent patch "fixes unnecessary seq id jump"
the SCST module fcst stopped working because multi-sequence
write data wasn't finding the sequence after the first frame.

Add back the setting of the seq_id when the first frame arrives.
Also fix indentation on two lines.

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>