drm/v3d: Set dma_mask as well as coherent_dma_mask

Both coherent_dma_mask and dma_mask act as constraints on allocations
and bounce buffer usage, so be sure to set dma_mask to the appropriate
value otherwise the effective mask could be incorrect.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/1608755714-18233-3-git-send-email-stefan.wahren@i2se.com