dmaengine: bcm2835: Print error in case setting DMA mask fails

During enabling of the RPi 4, we found out that the driver doesn't provide
a helpful error message in case setting DMA mask fails. So add one.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/1563297318-4900-1-git-send-email-wahrenst@gmx.net
Signed-off-by: Vinod Koul <vkoul@kernel.org>