arm64: defconfig: Enable CONFIG_KEYBOARD_SNVS_PWRKEY as module

Enable CONFIG_KEYBOARD_SNVS_PWRKEY as module to support i.MX8M
series SoCs' power key.
Signed-off-by: NAnson Huang <Anson.Huang@nxp.com>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>

arch/arm64/configs/defconfig

@@ -291,6 +291,7 @@ CONFIG_WLCORE_SDIO=m
 CONFIG_INPUT_EVDEV=y
 CONFIG_KEYBOARD_ADC=m
 CONFIG_KEYBOARD_GPIO=y
+CONFIG_KEYBOARD_SNVS_PWRKEY=m
 CONFIG_KEYBOARD_CROS_EC=y
 CONFIG_INPUT_TOUCHSCREEN=y
 CONFIG_TOUCHSCREEN_ATMEL_MXT=m