power: supply: mt6370: Fix missing error code in mt6370_chg_toggle_cfo()

power: supply: mt6370: Fix missing error code in mt6370_chg_toggle_cfo()

When mt6370_chg_field_get() suceeds, ret is set to zero and returning
zero when flash led is still in strobe mode looks incorrect.

Fixes: 233cb8a47d65 ("power: supply: mt6370: Add MediaTek MT6370 charger driver")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: ChiaEn Wu <chiaen_wu@richtek.com>
Link: https://lore.kernel.org/r/20230906084815.2827930-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>