Added DMA driver changes for Stoney platform.
Below are the key differences between Stoney and CZ

In Stoney, Memory Gating is disabled.SRAM Banks won't
be turned off.No Of SRAM Banks reduced to 6.
DAGB Garlic Interface used and 16 bit resolution is supported.
SRAM bank 1 & SRAM bank 2 will be used for playback scenario.
SRAM Bank 3 & SRAM Bank 4 will be used for Capture scenario.
Acked-by: NMark Brown <broonie@kernel.org>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NVijendar Mukunda <Vijendar.Mukunda@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NMark Brown <broonie@kernel.org>