Add a compatible string and clock mapping table to support ASRC on the
i.MX952 platform.

There is a limitation on i.MX952 that dma request is not cleared at the
end of conversion with dma slave mode. Which causes sample is dropped
from the input fifo on the second time if dma is triggered before the
client device and EDMA may copy wrong data from output fifo as the output
fifo is not ready in the beginning.

So need to trigger asrc before dma on i.MX952, and add delay to wait
output data is generated then start the EDMA for output, otherwise the
m2m function has noise issues.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>

This patch does more than one logical change. 

I would split in two patches:

- 1) introduce functionality to start ASRC before DMA.

- 2) add imx952 support including clk_map and introduce fsl_asrc_imx952_data

Thanks,

Daniel.