staging: mt7621-dts: use standard 'syscon' string

Both 'memc' and 'sysc' nodes are not using 'syscon'
as a node string which is the standard one to be used.
Update both of them.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20210505132154.8263-3-sergio.paracuellos@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-dts/mt7621.dtsi

@@ -55,7 +55,7 @@
 		#address-cells = <1>;
 		#size-cells = <1>;
 
-		sysc: sysc@0 {
+		sysc: syscon@0 {
 			compatible = "mediatek,mt7621-sysc", "syscon";
 			reg = <0x0 0x100>;
 			#clock-cells = <1>;
@@ -122,7 +122,7 @@
 			status = "disabled";
 		};
 
-		memc: memc@5000 {
+		memc: syscon@5000 {
 			compatible = "mediatek,mt7621-memc", "syscon";
 			reg = <0x5000 0x1000>;
 		};