Bluetooth: btmrvl: operate on 16-bit opcodes instead of ogf/ocf

Replace ogf/ocf and its packing with 16-bit opcodes.

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>