arm64: defconfig: Enable CONFIG_PINCTRL_IMX8DXL by default

Enable CONFIG_PINCTRL_IMX8DXL by default to support i.MX8DXL
pinctrl driver.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>