Bluetooth: btmrvl: fix firmware dump issue

Bluetooth: btmrvl: fix firmware dump issue

First firmware dump attempt from user works fine, but firmware goes
into bad state after this. Subsequent attempts fails.

As required by the firmware dump implementation, this change writes
FW_DUMP_READ_DONE value to dump ctrl register to address this issue.

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