Stoney uses 16kb SRAM memory for playback and 16Kb
for capture.Modified Max buffer size to have the
correct mapping between System Memory and SRAM.

Added snd_pcm_hardware structures for playback
and capture for Stoney.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mark Brown <broonie@kernel.org>