MAINTAINERS: update mt76 reviewers

Roy no longer works here. Time to say goodbye, my friend.
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/c171e0dfce9f2dad5ca6935eaf6004117f82e259.1587195398.git.ryder.lee@mediatek.com

MAINTAINERS

@@ -10694,7 +10694,6 @@ MEDIATEK MT76 WIRELESS LAN DRIVER
 M:	Felix Fietkau <nbd@nbd.name>
 M:	Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
 R:	Ryder Lee <ryder.lee@mediatek.com>
-R:	Roy Luo <royluo@google.com>
 L:	linux-wireless@vger.kernel.org
 S:	Maintained
 F:	drivers/net/wireless/mediatek/mt76/