misc: fastrpc: Add dma_mask to fastrpc_channel_ctx

dma_set_mask_and_coherent only updates the mask to which the device
dma_mask pointer points to. Add a dma_mask to the channel ctx and set
the device dma_mask to point to that, otherwise the dma_set_mask will
return an error and the dma_set_coherent_mask will be skipped too.

Co-developed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20221125071405.148786-11-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/fastrpc.c

@@ -278,6 +278,7 @@ struct fastrpc_channel_ctx {
 	struct list_head invoke_interrupted_mmaps;
 	bool secure;
 	bool unsigned_support;
+	u64 dma_mask;
 };
 
 struct fastrpc_device {
@@ -2303,6 +2304,7 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 	kref_init(&data->refcount);
 
 	dev_set_drvdata(&rpdev->dev, data);
+	rdev->dma_mask = &data->dma_mask;
 	dma_set_mask_and_coherent(rdev, DMA_BIT_MASK(32));
 	INIT_LIST_HEAD(&data->users);
 	INIT_LIST_HEAD(&data->invoke_interrupted_mmaps);