[S390] cio: Correct use of ! and &

In commit e6bafba5b4, a bug was fixed that
involved converting !x & y to !(x & y).  The code below shows the same
pattern, and thus should perhaps be fixed in the same way.  In particular,
the result of !scsw_stctl(&request->irb.scsw) & SCSW_STCTL_STATUS_PEND is
always just !scsw_stctl(&request->irb.scsw).

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: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/chsc_sch.c

@@ -261,7 +261,7 @@ static int chsc_examine_irb(struct chsc_request *request)
 {
 	int backed_up;
 
-	if (!scsw_stctl(&request->irb.scsw) & SCSW_STCTL_STATUS_PEND)
+	if (!(scsw_stctl(&request->irb.scsw) & SCSW_STCTL_STATUS_PEND))
 		return -EIO;
 	backed_up = scsw_cstat(&request->irb.scsw) & SCHN_STAT_CHAIN_CHECK;
 	request->irb.scsw.cmd.cstat &= ~SCHN_STAT_CHAIN_CHECK;