wifi: rtw88: phy: fix warning of possible buffer overflow

reported by smatch

phy.c:854 rtw_phy_linear_2_db() error: buffer overflow 'db_invert_table[i]'
8 <= 8 (assuming for loop doesn't break)

However, it seems to be a false alarm because we prevent it originally via
       if (linear >= db_invert_table[11][7])
               return 96; /* maximum 96 dB */

Still, we adjust the code to be more readable and avoid smatch warning.
Signed-off-by: NZong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: NPing-Ke Shih <pkshih@realtek.com>
Signed-off-by: NKalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220727065003.28340-5-pkshih@realtek.com

drivers/net/wireless/realtek/rtw88/phy.c

@@ -816,23 +816,18 @@ static u8 rtw_phy_linear_2_db(u64 linear)
 	u8 j;
 	u32 dB;
 
-	if (linear >= db_invert_table[11][7])
-		return 96; /* maximum 96 dB */
-
 	for (i = 0; i < 12; i++) {
-		if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][7])
-			break;
-		else if (i > 2 && linear <= db_invert_table[i][7])
-			break;
+		for (j = 0; j < 8; j++) {
+			if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][j])
+				goto cnt;
+			else if (i > 2 && linear <= db_invert_table[i][j])
+				goto cnt;
+		}
 	}
 
-	for (j = 0; j < 8; j++) {
-		if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][j])
-			break;
-		else if (i > 2 && linear <= db_invert_table[i][j])
-			break;
-	}
+	return 96; /* maximum 96 dB */
 
+cnt:
 	if (j == 0 && i == 0)
 		goto end;