mmc: omap: Use dma_request_chan() for requesting DMA channel
With the new dma_request_chan() the client driver does not need to look for
the DMA resource and it does not need to pass filter_fn anymore.
By switching to the new API the driver can now support deferred probing
against DMA.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> CC: Ulf Hansson <ulf.hansson@linaro.org> CC: Jarkko Nikula <jarkko.nikula@bitmer.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>