[media] au0828: Fix dev_state handling

The au0828 dev_state is actually a bit mask. It should not be
checking with "==" but, instead, with a logic and. There are some
places where it was doing it wrong.

Fix that by replacing the dev_state set/clear/test with the
bitops.

As reviewed by Shuah:
	"Looks good. Tested running bind/unbind au0828 loop for 1000 times.
	Didn't see any problems and the v4l2_querycap() problem has been
	fixed with this patch.

	After the above test, ran bind/unbind snd_usb_audio 1000 times.
	Didn't see any problems. Generated media graph and the graph
	looks good."

Cc: stable@vger.kernel.org
Reviewed-by: Shuah Khan <shuahkh@osg.samsung.com>
Tested-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>