Bluetooth: Use MD SET register for changing SDIO Type-B to Type-A

The register for setting the SDIO card mode of a Type-B Bluetooth card
is called MD SET. The MD STAT register is used for reading the current
mode back.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>