staging: gdm724x: Fix DMA from stack

Stack allocated buffers cannot be used for DMA
on all architectures so allocate usbdev buffer
using kmalloc().

Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>

drivers/staging/gdm724x/gdm_usb.c

@@ -56,7 +56,7 @@ static int gdm_usb_recv(void *priv_dev,
 
 static int request_mac_address(struct lte_udev *udev)
 {
-	u8 buf[16] = {0,};
+	u8 *buf;
 	struct hci_packet *hci = (struct hci_packet *)buf;
 	struct usb_device *usbdev = udev->usbdev;
 	int actual;
@@ -66,6 +66,10 @@ static int request_mac_address(struct lte_udev *udev)
 	hci->len = gdm_cpu_to_dev16(udev->gdm_ed, 1);
 	hci->data[0] = MAC_ADDRESS;
 
+	buf = kmalloc(16, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
 	ret = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 2), buf, 5,
 			   &actual, 1000);