ath79: rename tl-archer-c7 to archer-c7

This router is called Archer C7 and the tl was used to identify
TP-LINK. Since we have added tplink in dts/board name, the tl
prefix is useless now.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>

target/linux/ath79/dts/qca9558_tplink_archer-c7-v2.dts

@@ -4,10 +4,10 @@
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/input/input.h>
 
-#include "qca9558_tplink_tl-archer-c7.dtsi"
+#include "qca9558_tplink_archer-c7.dtsi"
 
 / {
-	compatible = "tplink,tl-archer-c7-v2", "qca,qca9558";
+	compatible = "tplink,archer-c7-v2", "qca,qca9558";
 	model = "TP-Link Archer C7 Version 2";
 };