Bluetooth: btusb: mediatek: add MediaTek devcoredump support

This patch implement function .coredump() and dmp_hdr() in btusb
driver for MediaTek controller.  FW core dump was triggered by FW
specific event to show something unexpected happened in the controller.

The driver would be responsible for collecting and uploading the device
core dump pieces in hci driver using core dump API. Once we finished
the whole process, the driver would reset the controller to recover the
kind of fatal error.

Co-developed-by: Chris Lu <chris.lu@mediatek.com>
Signed-off-by: Chris Lu <chris.lu@mediatek.com>
Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Jing Cai <jing.cai@mediatek.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>