arm64: dts: mt8173: add uart aliases

Add serial as uart aliases in mt8173.
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20200210063523.133333-3-hsinyi@chromium.orgSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt8173.dtsi

@@ -50,6 +50,10 @@ aliases {
 		mdp_wdma0 = &mdp_wdma0;
 		mdp_wrot0 = &mdp_wrot0;
 		mdp_wrot1 = &mdp_wrot1;
+		serial0 = &uart0;
+		serial1 = &uart1;
+		serial2 = &uart2;
+		serial3 = &uart3;
 	};
 
 	cluster0_opp: opp_table0 {