Bluetooth: btmtksdio: explicitly set WHISR as write-1-clear

That is a preliminary patch to introduce mt7921s support.

Explicitly set WHISR as write-1-clear method to all devices that is
the expected behavior the driver rely on.

Co-developed-by: Mark-yw Chen <mark-yw.chen@mediatek.com>
Signed-off-by: Mark-yw Chen <mark-yw.chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>