wlcore: debugfs: Remove unused variable 'res'

Fixes the following W=1 kernel build warning(s):

Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Luciano Coelho <luciano.coelho@nokia.com>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200826093401.1458456-16-lee.jones@linaro.org

drivers/net/wireless/ti/wlcore/debugfs.h

@@ -78,12 +78,12 @@ static ssize_t sub## _ ##name## _read(struct file *file,		\
 	struct wl1271 *wl = file->private_data;				\
 	struct struct_type *stats = wl->stats.fw_stats;			\
 	char buf[DEBUGFS_FORMAT_BUFFER_SIZE] = "";			\
-	int res, i;							\
+	int i;								\
 									\
 	wl1271_debugfs_update_stats(wl);				\
 									\
 	for (i = 0; i < len; i++)					\
-		res = snprintf(buf, sizeof(buf), "%s[%d] = %d\n",	\
+		snprintf(buf, sizeof(buf), "%s[%d] = %d\n",		\
 			 buf, i, stats->sub.name[i]);			\
 									\
 	return wl1271_format_buffer(userbuf, count, ppos, "%s", buf);	\