mt76x2: fix is_mt7612 routine

Fix is_mt7612 routine since asic version is set in mt76_dev revision
field and not in mt76x2_dev one.
Moreover remove mt76x2_dev rev field since it is never used in the
driver

Fixes: 7bc04215 ('mt76: add driver code for MT76x2e')
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Acked-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/mediatek/mt76/mt76x2.h

@@ -117,7 +117,6 @@ struct mt76x2_dev {
 	u8 beacon_mask;
 	u8 beacon_data_mask;
 
-	u32 rev;
 	u32 rxfilter;
 
 	u16 chainmask;
@@ -151,7 +150,7 @@ struct mt76x2_sta {
 
 static inline bool is_mt7612(struct mt76x2_dev *dev)
 {
-	return (dev->rev >> 16) == 0x7612;
+	return mt76_chip(&dev->mt76) == 0x7612;
 }
 
 void mt76x2_set_irq_mask(struct mt76x2_dev *dev, u32 clear, u32 set);