rtw88: remove redundant assignment to pointer debugfs_topdir

Pointer debugfs_topdir is initialized to a value that is never read
and it is re-assigned later. The initialization is redundant and can
be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -672,7 +672,7 @@ static struct rtw_debugfs_priv rtw_debug_priv_rsvd_page = {
 
 void rtw_debugfs_init(struct rtw_dev *rtwdev)
 {
-	struct dentry *debugfs_topdir = rtwdev->debugfs;
+	struct dentry *debugfs_topdir;
 
 	debugfs_topdir = debugfs_create_dir("rtw88",
 					    rtwdev->hw->wiphy->debugfsdir);