Fuel Gauge: Add fuel gauging algorithms

FG module takes voltage, current and coulomb counter
readings from the PMIC, executes fuel gauging algorithms,
and outputs estimated battery state of charge to the
sysfs interface.

Change-Id: I182acbdb0bb69380a7452c1b3a99f198031fdf64
Signed-off-by: Max Herman <mherman@fsisys.com>
MFD: TWL6030_GPADC: set conversion sample type in the ioctl function

Sample type of the conversion was not set in the ioctl function
and it was with random value. As result - many attempts to start
GPADC conversion via ioctl function were ended with the EINVAL
error. This patch fixes it.

Change-Id: Id8dc13f9cb7f8b828bc6f74bcac4a47b269bb83c
Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@ti.com>
mfd: gpadc - remove sysfs value

Change-Id: I30d01cdc5b1d05581f4679582889b6c4d359c24a