Battery charging state machine contains many file changes.
This is the 1st part of the break down. Refactor original
test code into board dummy driver. Normalize charger API.
And import link's charger IC driver.
Signed-off-by: Rong Chang <rongchang@google.com>
BUG=chrome-os-partner:7855
TEST=build without warning and error
BOARD=bds make
BOARD=link make
BOARD=discovery make
Change-Id: I34b6e9862a45331378916bc77653d4adb22ca548