max17042_battery: Support CHARGE_COUNTER power supply attribute

This patch adds the support for CHARGE_COUNTER power supply attribute
to max17042/47 driver.

Note:QH(Charge Counter) register is not documented in max17042 the Spec.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>