Bluetooth: btmtksdio: fix up firmware download sequence

Bluetooth: btmtksdio: fix up firmware download sequence

[ Upstream commit 737cd06072a72e8984e41af8e5919338d0c5bf2b ]

Data RAM on the device have to be powered on before starting to download
the firmware.

Fixes: 9aebfd4a2200 ("Bluetooth: mediatek: add support for MediaTek MT7663S and MT7668S SDIO devices")
Co-developed-by: Mark Chen <Mark-YW.Chen@mediatek.com>
Signed-off-by: Mark Chen <Mark-YW.Chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>