[SCSI] libfc: Correct use of ! and &

!ep->esb_stat is either 1 or 0, and the rightmost bit of ESB_ST_COMPLETE is
always 0, making the result of !ep->esb_stat & ESB_ST_COMPLETE always 0.
Thus parentheses around the argument to ! seem needed.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@ expression E; constant C; @@
(
  !E & !C
|
- !E & C
+ !(E & C)
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/libfc/fc_exch.c

@@ -281,7 +281,7 @@ static void fc_exch_release(struct fc_exch *ep)
 			ep->destructor(&ep->seq, ep->arg);
 		if (ep->lp->tt.exch_put)
 			ep->lp->tt.exch_put(ep->lp, mp, ep->xid);
-		WARN_ON(!ep->esb_stat & ESB_ST_COMPLETE);
+		WARN_ON(!(ep->esb_stat & ESB_ST_COMPLETE));
 		mempool_free(ep, mp->ep_pool);
 	}
 }