MAINTAINERS: mt76: add git tree

Felix has a git tree for mt76 patches, document that.
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230614144704.505553-1-kvalo@kernel.org

MAINTAINERS

@@ -13212,6 +13212,7 @@ R:	Shayne Chen <shayne.chen@mediatek.com>
 R:	Sean Wang <sean.wang@mediatek.com>
 L:	linux-wireless@vger.kernel.org
 S:	Maintained
+T:	git https://github.com/nbd168/wireless
 F:	Documentation/devicetree/bindings/net/wireless/mediatek,mt76.yaml
 F:	drivers/net/wireless/mediatek/mt76/