V4L/DVB (11063): au8522: power down the digital demod when not in use

When the au8522 is idle, put the chip into a low power mode (reduces power
consumption from 450ma to 346ma)

Thanks to Michael Krufky <mkrufky@linuxtv.org> and Steven Toth
<stoth@linuxtv.org> for providing sample hardware, engineering level support,
and testing.
Signed-off-by: Devin Heitmueller <dheitmueller@linuxtv.org>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/au8522_dig.c

@@ -617,6 +617,9 @@ int au8522_sleep(struct dvb_frontend *fe)
 	/* turn off led */
 	au8522_led_ctrl(state, 0);
 
+	/* Power down the chip */
+	au8522_writereg(state, 0xa4, 1 << 5);
+
 	state->current_frequency = 0;
 
 	return 0;