wwan: mhi: Fix missing spin_lock_init() in mhi_mbim_probe()

The driver allocates the spinlock but not initialize it.
Use spin_lock_init() on it to initialize it correctly.

Fixes: aa730a9 ("net: wwan: Add MHI MBIM network driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wwan/mhi_wwan_mbim.c

@@ -601,6 +601,7 @@ static int mhi_mbim_probe(struct mhi_device *mhi_dev, const struct mhi_device_id
 	if (!mbim)
 		return -ENOMEM;
 
+	spin_lock_init(&mbim->tx_lock);
 	dev_set_drvdata(&mhi_dev->dev, mbim);
 	mbim->mdev = mhi_dev;
 	mbim->mru = mhi_dev->mhi_cntrl->mru ? mhi_dev->mhi_cntrl->mru : MHI_DEFAULT_MRU;