mt76: fix variable gain adjustment range

The range should only be limited to 4 for really weak signals, for all
other gain settings the range is 16.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/mediatek/mt76/mt76x2_phy.c

@@ -485,7 +485,7 @@ static void
 mt76x2_phy_adjust_vga_gain(struct mt76x2_dev *dev)
 {
 	u32 false_cca;
-	u8 limit = dev->cal.low_gain > 1 ? 4 : 16;
+	u8 limit = dev->cal.low_gain > 0 ? 16 : 4;
 
 	false_cca = FIELD_GET(MT_RX_STAT_1_CCA_ERRORS, mt76_rr(dev, MT_RX_STAT_1));
 	if (false_cca > 800 && dev->cal.agc_gain_adjust < limit)