bq27x00_battery: Add support to bq27742

Add support to bq27742 in bq27x00 driver. bq27742 register
addresses are mostly mostly the same as bq27500 addresses
with minor differences.

Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Rhyland Klein <rklein@nvidia.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>