Bluetooth: hci_core: Fix not checking skb length on hci_acldata_packet

Bluetooth: hci_core: Fix not checking skb length on hci_acldata_packet

[ Upstream commit 3fe288a8214e7dd784d1f9b7c9e448244d316b47 ]

This fixes not checking if skb really contains an ACL header otherwise
the code may attempt to access some uninitilized/invalid memory past the
valid skb->data.

Reported-by: syzbot+6ea290ba76d8c1eb1ac2@syzkaller.appspotmail.com
Tested-by: syzbot+6ea290ba76d8c1eb1ac2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6ea290ba76d8c1eb1ac2
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>