staging: comedi: mf6x4: prefer using the BIT macro

Fix the checkpatch.pl issues.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
 drivers/staging/comedi/drivers/mf6x4.c | 9 ---------
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>