pmic:chrg: Common information about charger and battery (power_chrg.h)

New power_chrg.h file has been added to "bind" together common
information about charging battery available in the system.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Stefano Babic <sbabic@denx.de>