Properly check for an interrupted cv_wait_sig().

The returned error number may be EINTR or ERESTART depending on
whether or not the signal is supposed to interrupt the system call.

Reported and tested by:	pho
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation

sys/dev/sound/midi/sequencer.c

@@ -912,7 +912,7 @@ mseq_read(struct cdev *i_dev, struct uio *uio, int ioflag)
 				goto err1;
 
 			retval = cv_wait_sig(&scp->in_cv, &scp->seq_lock);
-			if (retval == EINTR)
+			if (retval != 0)
 				goto err1;
 		}
 
@@ -977,7 +977,7 @@ mseq_write(struct cdev *i_dev, struct uio *uio, int ioflag)
 		         * We slept, maybe things have changed since last
 		         * dying check
 		         */
-			if (retval == EINTR)
+			if (retval != 0)
 				goto err0;
 #if 0
 			/*