of: Return success from of_dma_set_restricted_buffer() when !OF_ADDRESS

When CONFIG_OF_ADDRESS=n, of_dma_set_restricted_buffer() returns -ENODEV
and breaks the boot for sparc[64] machines. Return 0 instead, since the
function is essentially a glorified NOP in this configuration.

Cc: Claire Chang <tientzu@chromium.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Claire Chang <tientzu@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210702030807.GA2685166@roeck-us.net
Fixes: fec9b62 ("of: Add plumbing for restricted DMA pool")
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad@kernel.org>

drivers/of/of_private.h

@@ -173,7 +173,8 @@ static inline int of_dma_get_range(struct device_node *np,
 static inline int of_dma_set_restricted_buffer(struct device *dev,
 					       struct device_node *np)
 {
-	return -ENODEV;
+	/* Do nothing, successfully. */
+	return 0;
 }
 #endif