power: supply: wm831x: Check wm831x_set_bits() return value

power: supply: wm831x: Check wm831x_set_bits() return value

Since wm831x_set_bits() may return error, log failure and exit from
wm831x_usb_limit_change() in such case.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 626b6cd5f52e ("power: wm831x_power: Support USB charger current limit management")
Signed-off-by: Ivan Abramov <i.abramov@mt-integration.ru>
Link: https://patch.msgid.link/20251009170553.566561-1-i.abramov@mt-integration.ru
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>