Bluetooth: Fix complicated assignment of firmware for Marvell devices

The Marvell Bluetooth SDIO driver has a really complicated concept on how
firmware names are assigned to specific device ids. Fix that by doing a
proper structure and assign it to the module device table.

And while at it fix various coding style weirdness that is still present
in this driver.

Signed-off-by: Marcel Holtman <marcel@holtmann.org>