ramips: restore full switch performance for USW-Flex

Since commit f1c9afd801 ("ramips: mt7621-dts: mux phy0/4 to gmac1") the
USW-Flex lan1 port has been attached directly to the CPU. This improves
routing performance but hinders switching.

This is a generally accepted trade-off in that commit but for USW-Flex it
is a questionable choice. This switch is designed to deliver PoE to remote
places and using it as a router is unlikely. Meanwhile, the lan1 port is
also PoE-in and will often be the uplink, carrying most of the traffic.

Reverting f1c9afd801 for USW-Flex restores full 1 Gbps switching
performance on all ports.

Signed-off-by: Anders Melchiorsen <amelchio@nogoto.net>
Link: https://github.com/openwrt/openwrt/pull/17703
Signed-off-by: Robert Marko <robimarko@gmail.com>
(cherry picked from commit 62872f8bfd5c8bc80bb014417c6ed8057bbeb773)

target/linux/ramips/dts/mt7621_ubnt_usw-flex.dts

@@ -64,19 +64,6 @@
 	label = "dsa";
 };
 
-&gmac1 {
-	status = "okay";
-	label = "lan1";
-	phy-handle = <&ethphy4>;
-
-	nvmem-cells = <&macaddr_eeprom>;
-	nvmem-cell-names = "mac-address";
-};
-
-&ethphy4 {
-	/delete-property/ interrupts;
-};
-
 &switch0 {
 	ports {
 		port@0 {
@@ -98,6 +85,11 @@
 			status = "okay";
 			label = "lan2";
 		};
+
+                port@4 {
+                        status = "okay";
+                        label = "lan1";
+                };
 	};
 };