staging: btmtk_usb: use GFP_KERNEL inplace of GFP_ATOMIC in _probe path

the _probe function doesn't run in interrupt context, so no need to use
the GFP_ATOMIC allocations, instead driver can request for GFP_KERNEL
Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/btmtk_usb/btmtk_usb.c

@@ -1596,7 +1596,7 @@ static int btmtk_usb_probe(struct usb_interface *intf,
 		}
 	}
 
-	data->io_buf = kmalloc(256, GFP_ATOMIC);
+	data->io_buf = kmalloc(256, GFP_KERNEL);
 	if (!data->io_buf) {
 		hci_free_dev(hdev);
 		kfree(data);