drm/amdgpu: create I2S platform devices for Jadeite platform

Jadeite platform uses I2S MICSP instance.
Create platform devices for DMA controller and I2S controller for
Jadeite platform.
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>