add below firmware:
BR2_PACKAGE_STARFIVE_FIRMWARE_AP6256_BLUETOOTH
BR2_PACKAGE_STARFIVE_FIRMWARE_AP6256_SDIO_WIFI
add ap6256 bluetooth and sdio wifi firmware
files to /lib/firmware/.
for addtional firmware file, we can also add it
like this way.
Signed-off-by: Andy Hu <andy.hu@starfivetech.com>