ARM: configs: sunxi: Enable the PS/2 controller

The A20 has a PS/2 controller and we have a driver for it, so let's enable
it in our defconfig.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20200706132323.147562-1-maxime@cerno.tech

arch/arm/configs/sunxi_defconfig

@@ -59,6 +59,7 @@ CONFIG_INPUT_TOUCHSCREEN=y
 CONFIG_TOUCHSCREEN_SUN4I=y
 CONFIG_INPUT_MISC=y
 CONFIG_INPUT_AXP20X_PEK=y
+CONFIG_SERIO_SUN4I_PS2=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_8250_NR_UARTS=8