firewire: sbp2: bring back WRITE SAME support

Commit 54b2b50c "[SCSI] Disable WRITE SAME for RAID and virtual
host adapter drivers" disabled WRITE SAME support for all SBP-2 attached
targets.  But as described in the changelog of commit b0ea5f19
"firewire: sbp2: allow WRITE SAME and REPORT SUPPORTED OPERATION CODES",
it is not required to blacklist WRITE SAME.

Bring the feature back by reverting the sbp2.c hunk of commit 54b2b50c.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: stable@kernel.org