Bluetooth: btmtksdio: fix the reset takes too long

Sending WMT command during the reset in progress is invalid and would get
no response from firmware until the reset is complete, so we ignore the WMT
command here to resolve the issue which causes the whole reset process
taking too long.

Fixes: 8fafe702 ("Bluetooth: mt7921s: support bluetooth reset mechanism")
Co-developed-by: Yake Yang <yake.yang@mediatek.com>
Signed-off-by: Yake Yang <yake.yang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>