wifi: rtw89: debug: fix error code in rtw89_debug_priv_send_h2c_set()

If there is a failure during rtw89_fw_h2c_raw() rtw89_debug_priv_send_h2c
should return negative error code instead of a positive value count.
Fix this bug by returning correct error code.

Fixes: e3ec7017f6 ("rtw89: add Realtek 802.11ax driver")
Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://lore.kernel.org/r/tencent_AD09A61BC4DA92AD1EB0790F5C850E544D07@qq.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -3026,17 +3026,18 @@ static ssize_t rtw89_debug_priv_send_h2c_set(struct file *filp,
 	struct rtw89_debugfs_priv *debugfs_priv = filp->private_data;
 	struct rtw89_dev *rtwdev = debugfs_priv->rtwdev;
 	u8 *h2c;
+	int ret;
 	u16 h2c_len = count / 2;
 
 	h2c = rtw89_hex2bin_user(rtwdev, user_buf, count);
 	if (IS_ERR(h2c))
 		return -EFAULT;
 
-	rtw89_fw_h2c_raw(rtwdev, h2c, h2c_len);
+	ret = rtw89_fw_h2c_raw(rtwdev, h2c, h2c_len);
 
 	kfree(h2c);
 
-	return count;
+	return ret ? ret : count;
 }
 
 static int