Add a general twl device driver twlcore to call i2c send/write
functions.
Abstract twl4030 to call twlcore functions.
Fixed some code-styling issues pointed out by checkpatch.
Signed-off-by: Alexander Aring <a.aring@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>