comedi vmk80xx: extend rudimentary_check to check both directions

rudimentary_check() can currently check whether the input or
output direction is currently available (no pending transaction),
but not both at the same time. We need this facility for do_bits().
Signed-off-by: NJ. Ali Harlow <ali@avrc.city.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/comedi/drivers/vmk80xx.c

@@ -568,7 +568,8 @@ static int rudimentary_check(struct vmk80xx_usb *dev, int dir)
 	if (dir & DIR_IN) {
 		if (test_bit(TRANS_IN_BUSY, &dev->flags))
 			return -EBUSY;
-	} else {  /* DIR_OUT */
+	}
+	if (dir & DIR_OUT) {
 		if (test_bit(TRANS_OUT_BUSY, &dev->flags))
 			return -EBUSY;
 	}