dmaengine: Add DMA_PRIVATE to BCM2835 driver

Without DMA_PRIVATE the driver is not able to allocate more than one channel.
Since it uses dma_get_any_slave_channel that calls private_candidate,
the second allocation fails at
/* some channels are already publicly allocated */
Maybe it should be fixed in the core, but at least this fixes the bug.
Signed-off-by: Florian Meier <florian.meier@koalo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/bcm2835-dma.c

@@ -611,6 +611,7 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
 	od->base = base;
 
 	dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
+	dma_cap_set(DMA_PRIVATE, od->ddev.cap_mask);
 	dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask);
 	od->ddev.device_alloc_chan_resources = bcm2835_dma_alloc_chan_resources;
 	od->ddev.device_free_chan_resources = bcm2835_dma_free_chan_resources;