pinctrl: rockchip: return ENOMEM instead of EINVAL if allocation fails

The function rockchip_pinctrl_parse_dt returns -EINVAL if
allocation fails. Change the return error to -ENOMEM

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20200506101424.15691-1-dafna.hirschfeld@collabora.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>