[PATCH] wifi: rtw88: fix uninitialized use of primary channel index

[Ping-Ke Shih <pkshih@xxxxxxxxxxx>]

clang reports uninitialized use:

>> drivers/net/wireless/realtek/rtw88/main.c:731:2: warning: variable
   'primary_channel_idx' is used uninitialized whenever switch default is
   taken [-Wsometimes-uninitialized]
           default:
           ^~~~~~~
   drivers/net/wireless/realtek/rtw88/main.c:754:39: note: uninitialized
   use occurs here
           hal->current_primary_channel_index = primary_channel_idx;
                                                ^~~~~~~~~~~~~~~~~~~
   drivers/net/wireless/realtek/rtw88/main.c:687:24: note: initialize the
   variable 'primary_channel_idx' to silence this warning
           u8 primary_channel_idx;
                                 ^
                                  = '\0'

This situation could not happen, because possible channel bandwidth
20/40/80MHz are enumerated.

Fixes: 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting by parameters")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
---
 drivers/net/wireless/realtek/rtw88/main.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/main.c b/drivers/net/wireless/realtek/rtw88/main.c
index 790dcfed1125d..5a74dda977563 100644
--- a/drivers/net/wireless/realtek/rtw88/main.c
+++ b/drivers/net/wireless/realtek/rtw88/main.c
@@ -697,6 +697,7 @@ void rtw_update_channel(struct rtw_dev *rtwdev, u8 center_channel,
 
 	switch (bandwidth) {
 	case RTW_CHANNEL_WIDTH_20:
+	default:
 		primary_channel_idx = RTW_SC_DONT_CARE;
 		break;
 	case RTW_CHANNEL_WIDTH_40:
@@ -728,8 +729,6 @@ void rtw_update_channel(struct rtw_dev *rtwdev, u8 center_channel,
 			cch_by_bw[RTW_CHANNEL_WIDTH_40] = center_channel - 4;
 		}
 		break;
-	default:
-		break;
 	}
 
 	switch (center_channel) {
-- 
2.25.1