arm64: dts: meson-gxl-s905d-phicomm-n1: add status LED

There is a white LED on the front panel behind the logo and the
manufacturer uses that LED to indicate network and USB drive status.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>