DMA-API: staging: use dma_set_coherent_mask()

The correct way for a driver to specify the coherent DMA mask is
not to directly access the field in the struct device, but to use
dma_set_coherent_mask().  Only arch and bus code should access this
member directly.

Convert all direct write accesses to using the correct API.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --cc drivers/staging/dwc2/platform.c
Simple merge

diff --cc drivers/staging/imx-drm/imx-drm-core.c
Simple merge

diff --cc drivers/staging/imx-drm/ipuv3-crtc.c
Simple merge