Bluetooth: btmtk: apply the common btmtk_fw_get_filename

Apply the common btmtk_fw_get_filename to avoid the similar coding in each
driver.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2 files changed