Bluetooth: mediatek: Use module_sdio_driver helper
Macro module_sdio_driver is used for drivers whose init and exit paths
only register and unregister to SDIO API. So remove boilerplate code to
make code simpler by using module_sdio_driver.
Suggested-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sean Wang <sean.wang@mediatek.com> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>