drivers: twl4030_madc_battery: cleanup and fix reading values

Signed-off-by: Lukas Märdian <lukas@goldelico.com>
drivers/power: cleanup twl4030_madc_battery header

Signed-off-by: Lukas Märdian <luk@slyon.de>
drivers/power: Kconfig: twl4030_madc_battery depends on twl4030_madc

Signed-off-by: Lukas Märdian <lukas@goldelico.com>
Merge commit 'ee3ca2106a32524850902715fef42c64fd5e397b' into neil-3.1x-plus