arm64: dts: mt8173: add uart aliases

Add serial as uart aliases in mt8173.

Signed-off-by: Hsin-Yi Wang <[e-mail]>
Reviewed-by: Enric Balletbo i Serra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Matthias Brugger <[e-mail]>

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

···
 		mdp_wdma0 = &mdp_wdma0;
 		mdp_wrot0 = &mdp_wrot0;
 		mdp_wrot1 = &mdp_wrot1;
+		serial0 = &uart0;
+		serial1 = &uart1;
+		serial2 = &uart2;
+		serial3 = &uart3;
 	};
 
 	cluster0_opp: opp_table0 {