bluetooth: btusb: Replace GFP_ATOMIC with GFP_KERNEL in inject_cmd_complete()

inject_cmd_complete() is only called by btusb_send_frame_intel(),
which is set to hdev->send, and hdev->send() is never
called in atomic context.

inject_cmd_complete() calls bt_skb_alloc() with GFP_ATOMIC,
which is not necessary.
GFP_ATOMIC can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.
I also manually check the kernel code before reporting it.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btusb.c

@@ -1895,7 +1895,7 @@ static int inject_cmd_complete(struct hci_dev *hdev, __u16 opcode)
 	struct hci_event_hdr *hdr;
 	struct hci_ev_cmd_complete *evt;
 
-	skb = bt_skb_alloc(sizeof(*hdr) + sizeof(*evt) + 1, GFP_ATOMIC);
+	skb = bt_skb_alloc(sizeof(*hdr) + sizeof(*evt) + 1, GFP_KERNEL);
 	if (!skb)
 		return -ENOMEM;