vhost/scsi: Drop left-over scsi_tcq.h include

With the recent removal of MSG_*_TAG defines in commit 68d81f40,
vhost-scsi is now using TCM_*_TAG and doesn't depend upon host
side scsi_tcq.h definitions anymore.

Cc: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>