arm64: dts: allwinner: pine64: Add remaining UART aliases

Enabling uart2 node currently leads to a /dev/ttyS1 device, with ttyS0..4
always present, causing confusion on the user's part.

dtc cannot resolve an overlay's &uart2 reference for strings, only for
phandles, so it would need to hardcode the full node path.

Avoid this and enforce reliable numbering by adding serialX aliases for:

UART1 - on Wifi/BT connector
UART2 - on Pi-2 connector
UART3 - on Euler connector
UART4 - on Euler connector
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm64/boot/dts/allwinner/sun50i-a64-pine64.dts

@@ -52,6 +52,10 @@ / {
 
 	aliases {
 		serial0 = &uart0;
+		serial1 = &uart1;
+		serial2 = &uart2;
+		serial3 = &uart3;
+		serial4 = &uart4;
 	};
 
 	chosen {