pcmcia: fix error handling in cm4000_cs.c

In the original code we used -ENODEV as the number of bytes to
copy_to_user() and we didn't release the locks.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

drivers/char/pcmcia/cm4000_cs.c

@@ -1026,14 +1026,16 @@ static ssize_t cmm_read(struct file *filp, __user char *buf, size_t count,
 
 	xoutb(0, REG_FLAGS1(iobase));	/* clear detectCMM */
 	/* last check before exit */
-	if (!io_detect_cm4000(iobase, dev))
-		count = -ENODEV;
+	if (!io_detect_cm4000(iobase, dev)) {
+		rc = -ENODEV;
+		goto release_io;
+	}
 
 	if (test_bit(IS_INVREV, &dev->flags) && count > 0)
 		str_invert_revert(dev->rbuf, count);
 
 	if (copy_to_user(buf, dev->rbuf, count))
-		return -EFAULT;
+		rc = -EFAULT;
 
 release_io:
 	clear_bit(LOCK_IO, &dev->flags);