This code sequence is unsafe in modules:

static u64 mask = DMA_BIT_MASK(something);
...
	if (!dev->dma_mask)
		dev->dma_mask = &mask;

as if a module is reloaded, the mask will be pointing at the original
module's mask address, and this can lead to oopses.  Moreover, they
all follow this with:

	if (!dev->coherent_dma_mask)
		dev->coherent_dma_mask = mask;

where 'mask' is the same value as the statically defined mask, and this
bypasses the architecture's check on whether the DMA mask is possible.

Fix these issues by using the new dma_coerce_coherent_and_mask()
function.
Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>