power: supply: core: fix typo in function to get current charge control limit

There is a spelling mistake in ps_get_cur_charge_cntl_limit function so
replace 'chrage' for 'charge'.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>