bluetooth: btmrvl: increase the priority of firmware download message

When driver is loaded, it is important to know if FW was already
active or it is freshly downloaded. This patch increases the
priority of the message.

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