wifi: rtw89: phy: fix uninitialized variable access in rtw89_phy_cfo_set_crystal_cap()

[ Upstream commit 047cddf ]

In the rtw89_phy_cfo_set_crystal_cap() function, for chips other than
RTL8852A/RTL8851B, the values read by rtw89_mac_read_xtal_si() are
stored into the local variables sc_xi_val and sc_xo_val. If either
read fails, these variables remain uninitialized, they are later
used to update cfo->crystal_cap and in debug print statements. This
can lead to undefined behavior.

Fix the issue by initializing sc_xi_val and sc_xo_val to zero,
like is implemented in vendor driver.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 8379fa6 ("rtw89: 8852c: add write/read crystal function in CFO tracking")
Signed-off-by: Alexey Velichayshiy <a.velichayshiy@ispras.ru>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260323140613.1615574-1-a.velichayshiy@ispras.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Alexey Velichayshiy

drivers/net/wireless/realtek/rtw89/phy.c

@@ -4499,7 +4499,7 @@ static void rtw89_phy_cfo_set_crystal_cap(struct rtw89_dev *rtwdev,
 {
 	struct rtw89_cfo_tracking_info *cfo = &rtwdev->cfo_tracking;
 	const struct rtw89_chip_info *chip = rtwdev->chip;
-	u8 sc_xi_val, sc_xo_val;
+	u8 sc_xi_val = 0, sc_xo_val = 0;
 
 	if (!force && cfo->crystal_cap == crystal_cap)
 		return;