Bluetooth: Move HCI socket definitions into its own header file

All the HCI sockets and ioctl based definitions have been in a global
header file that also includes all the HCI protocol structures. To
make this a bit cleaner, move them into its own file.

This also adjusts fs/compat_ioctl.c to only include this new file
and not all the protocol structures that are not needed.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>