drivers: remove force dma flag from buses

With each bus implementing its own DMA configuration callback, there is no
need for bus to explicitly set the force_dma flag.  Modify the
of_dma_configure function to accept an input parameter which specifies if
implicit DMA configuration is required when it is not described by the
firmware.

Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>  # PCI parts
Reviewed-by: Rob Herring <robh@kernel.org>
[hch: tweaked the changelog a bit]
Signed-off-by: Christoph Hellwig <hch@lst.de>