dt-bindings: mips: Add bindings for TP-Link HC220 G5 v1 board

Add bindings for the compatible string used for the TP-Link's
HC220 G5 V1 board, a wireless AP based on MT7621.

Signed-off-by: Liviu Dudau <[e-mail]>
Acked-by: Conor Dooley <[e-mail]>
Acked-by: Sergio Paracuellos <[e-mail]>
Signed-off-by: Thomas Bogendoerfer <[e-mail]>

Documentation/devicetree/bindings/mips/ralink.yaml

···
           - enum:
               - gnubee,gb-pc1
               - gnubee,gb-pc2
+              - tplink,hc220-g5-v1
           - const: mediatek,mt7621-soc
 
 additionalProperties: true