dmaengine: fix !of_dma compilation warning

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

include/linux/of_dma.h

@@ -44,7 +44,7 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
 		struct of_dma *ofdma);
 #else
-static int of_dma_controller_register(struct device_node *np,
+static inline int of_dma_controller_register(struct device_node *np,
 		struct dma_chan *(*of_dma_xlate)
 		(struct of_phandle_args *, struct of_dma *),
 		void *data)
@@ -52,17 +52,18 @@ static int of_dma_controller_register(struct device_node *np,
 	return -ENODEV;
 }
 
-static int of_dma_controller_free(struct device_node *np)
+static inline int of_dma_controller_free(struct device_node *np)
 {
+	return -ENODEV;
 }
 
-static struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
+static inline struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 						     char *name)
 {
 	return NULL;
 }
 
-static struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
+static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
 		struct of_dma *ofdma)
 {
 	return NULL;