hwmon: (mc13783-adc) Add support for the MC13892 PMIC

Based on a patch by David Jander that mostly did s/mc13783/mc13xxx/ .

Additionally use dev_get_drvdata instead of to_platform_device +
platform_get_drvdata in mc13783_adc_read (spotted by Jean Delvare).

Cc: David Jander <david.jander@protonic.nl>
Signed-off-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>