smb347-charger: Convert to regmap API

The smb347-charger driver does a lot of read-modify-write to the device
registers. Instead of open-coding everything we can take advantage of
regmap API which provides nice functions to do this kind of things.

In addition there is no need for custom debugfs file for dumping
registers as this is already provided by the regmap API.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NAnton Vorontsov <anton.vorontsov@linaro.org>

drivers/power/Kconfig

@@ -291,6 +291,7 @@ config CHARGER_MAX8998
 config CHARGER_SMB347
 	tristate "Summit Microelectronics SMB347 Battery Charger"
 	depends on I2C
+	select REGMAP_I2C
 	help
 	  Say Y to include support for Summit Microelectronics SMB347
 	  Battery Charger.