[PATCH v2] mt76/mt7915: Fix unsigned compared against zero

[John Wood]

The mt7915_dpd_freq_idx() function can return a negative value but this
value is assigned to an unsigned variable named idx. Then, the code
tests if this variable is less than zero. This can never happen with an
unsigned type.

So, change the idx type to a signed one.

Addresses-Coverity-ID: 1484753 ("Unsigned compared against 0")
Fixes: 495184ac91bb8 ("mt76: mt7915: add support for applying pre-calibration data")
Signed-off-by: John Wood <john.wood@xxxxxxx>
---
Changelog v1 -> v2
- Add Cc to stable@xxxxxxxxxxxxxxx

 drivers/net/wireless/mediatek/mt76/mt7915/mcu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
index b3f14ff67c5a..764f25a828fa 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
@@ -3440,8 +3440,9 @@ int mt7915_mcu_apply_tx_dpd(struct mt7915_phy *phy)
 {
 	struct mt7915_dev *dev = phy->dev;
 	struct cfg80211_chan_def *chandef = &phy->mt76->chandef;
-	u16 total = 2, idx, center_freq = chandef->center_freq1;
+	u16 total = 2, center_freq = chandef->center_freq1;
 	u8 *cal = dev->cal, *eep = dev->mt76.eeprom.data;
+	int idx;

 	if (!(eep[MT_EE_DO_PRE_CAL] & MT_EE_WIFI_CAL_DPD))
 		return 0;
--
2.25.1