usb: gadget: don't fail when DMA isn't present

When CONFIG_HAS_DMA isn't enabled, the UDC core gets build errors:

drivers/built-in.o: In function `dma_set_coherent_mask':
include/linux/dma-mapping.h:93: undefined reference to `dma_supported'
include/linux/dma-mapping.h:93: undefined reference to `dma_supported'
drivers/built-in.o: In function `usb_gadget_unmap_request':
drivers/usb/gadget/udc-core.c:91: undefined reference to `dma_unmap_sg'
drivers/usb/gadget/udc-core.c:96: undefined reference to `dma_unmap_single'
drivers/built-in.o: In function `usb_gadget_map_request':
drivers/usb/gadget/udc-core.c:62: undefined reference to `dma_map_sg'
drivers/usb/gadget/udc-core.c:71: undefined reference to `dma_map_single'
drivers/usb/gadget/udc-core.c:74: undefined reference to `dma_mapping_error'

Prevent this by protecting the DMA API routines with preprocessor tests.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/udc-core.c

@@ -50,6 +50,8 @@ static DEFINE_MUTEX(udc_lock);
 
 /* ------------------------------------------------------------------------- */
 
+#ifdef	CONFIG_HAS_DMA
+
 int usb_gadget_map_request(struct usb_gadget *gadget,
 		struct usb_request *req, int is_in)
 {
@@ -99,6 +101,8 @@ void usb_gadget_unmap_request(struct usb_gadget *gadget,
 }
 EXPORT_SYMBOL_GPL(usb_gadget_unmap_request);
 
+#endif	/* CONFIG_HAS_DMA */
+
 /* ------------------------------------------------------------------------- */
 
 void usb_gadget_set_state(struct usb_gadget *gadget,
@@ -194,9 +198,11 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
 	dev_set_name(&gadget->dev, "gadget");
 	gadget->dev.parent = parent;
 
+#ifdef	CONFIG_HAS_DMA
 	dma_set_coherent_mask(&gadget->dev, parent->coherent_dma_mask);
 	gadget->dev.dma_parms = parent->dma_parms;
 	gadget->dev.dma_mask = parent->dma_mask;
+#endif
 
 	if (release)
 		gadget->dev.release = release;