There is no check that allocation in axp20x_funcs_groups_from_mask
is successful.
The patch adds corresponding check and return values.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAnton Vasilyev <vasilyev@ispras.ru>
Acked-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>