ramips: specify "firmware" partition format for remaining devices

It results in calling the right MTD parser directly instead of trying
them one by one.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
[use the lzma splitter for the AR670W]
Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/ramips/dts/AR670W.dts

@@ -39,6 +39,7 @@
 			};
 
 			partition@40000 {
+				compatible = "lzma";
 				reg = <0x40000 0x3c0000>;
 				label = "firmware";
 			};

target/linux/ramips/dts/DAP-1522-A1.dts

@@ -40,6 +40,7 @@
 			};
 
 			partition@40000 {
+				compatible = "wrg";
 				label = "firmware";
 				reg = <0x40000 0x3a0000>;
 			};

target/linux/ramips/dts/WCR-1166DS.dts

@@ -152,6 +152,7 @@
 			};
 
 			partition@50000 {
+				compatible = "openwrt,trx";
 				label = "firmware";
 				reg = <0x50000 0x7c0000>;
 			};