Bluetooth: btmrvl: support Marvell Bluetooth device SD8797

The SD8797 firmware image is shared with mwifiex driver.
Whoever gets loaded first will be responsible for firmware
downloading.

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Frank Huang <frankh@marvell.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>