mfd: twl4030-madc: Add support for raw value in twl4030_madc_conversion

mfd: twl4030-madc: Add support for raw value in twl4030_madc_conversion

Driver twl4030-madc has hardcoded channel types (10 - battery current,
1 - battery temperature) and also conversation data in variable
twl4030_divider_ratios. These hardcoded channels are incorrect for
Nokia RX-51 board (where is channel 0 - battery temperature).

For Nokia RX-51 there is rx51_battery power_supply driver which reporting
battery information via twl4030_madc_conversion. But this driver needs
raw values (not converted via some hardcoded functions). So this patch
adding new parameter "raw" to struct twl4030_madc_request which tell
twl4030-madc driver to not convert values, but rather return raw.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>