Bluetooth: btrtl: Add RTL8723D and RTL8821C devices

The Bluetooth parts of RTL8723D and RTL8723B share the same lmp
subversion, thus we need to check both lmp subversion and hci revision
to distinguish the two. The same situation is true for RTL8821A and
RTL8821C. Accordingly, the selection code is revised.

To improve maintainability, a new id_table struct is defined, and an
array of such structs is constructed. Adding a new device can thus be
as simple as adding another value to the table.

Signed-off-by: Alex Lu <alex_lu@realsil.com.cn>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>