HID: intel_ish-hid: tx_buf memory leak on probe/remove

ish_dev_init() allocates 512*176 bytes memory for tx_buf and stores it at
&dev->wr_free_list_head.link list on ish_probe().
But there is no deallocation of this memory in ish_remove() and in
ish_probe() error path.
So current intel-ish-ipc provides 88 KB memory leak for each
probe/release.

The patch replaces kzalloc allocation by devm_kzalloc and removes
ishtp_device *dev deallocation by kfree.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <[e-mail]>
Acked-by: Srinivas Pandruvada <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/intel-ish-hid/ipc/ipc.c

···
 	struct ishtp_device *dev;
 	int	i;
 
-	dev = kzalloc(sizeof(struct ishtp_device) + sizeof(struct ish_hw),
-		GFP_KERNEL);
+	dev = devm_kzalloc(&pdev->dev,
+			   sizeof(struct ishtp_device) + sizeof(struct ish_hw),
+			   GFP_KERNEL);
 	if (!dev)
 		return NULL;
 
···
 	for (i = 0; i < IPC_TX_FIFO_SIZE; ++i) {
 		struct wr_msg_ctl_info	*tx_buf;
 
-		tx_buf = kzalloc(sizeof(struct wr_msg_ctl_info), GFP_KERNEL);
+		tx_buf = devm_kzalloc(&pdev->dev,
+				      sizeof(struct wr_msg_ctl_info),
+				      GFP_KERNEL);
 		if (!tx_buf) {
 			/*
 			 * IPC buffers may be limited or not available

drivers/hid/intel-ish-hid/ipc/pci-ish.c

···
 	free_irq(pdev->irq, dev);
 free_device:
 	pci_iounmap(pdev, hw->mem_addr);
-	kfree(dev);
 release_regions:
 	pci_release_regions(pdev);
 disable_device:
···
 	pci_release_regions(pdev);
 	pci_clear_master(pdev);
 	pci_disable_device(pdev);
-	kfree(ishtp_dev);
 }
 
 static struct device __maybe_unused *ish_resume_device;