dma-direct: don't check swiotlb=force in dma_direct_map_resource

When mapping resources we can't just use swiotlb ram for bounce
buffering.  Switch to a direct dma_capable check instead.

Fixes: cfced786 ("dma-mapping: remove the default map_resource implementation")
Reported-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>