fw_sst_0f28: Add firmware for Intel Baytrail SST DSP

Add firmware file and licence for Intel Baytrail SST DSP audio.
The firmware is distributed under Intel Free Redistribution License.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mengdong Lin <mengdong.lin@intel.com>
Signed-off-by: Kyle McMartin <kyle@kernel.org>