usb: gadget: net2272: finally convert "CONFIG_USB_GADGET_NET2272_DMA"

The Kconfig symbol USB_GADGET_NET2272_DMA was renamed to USB_NET2272_DMA
in commit 193ab2a6 ("usb: gadget: allow
multiple gadgets to be built"). That commit did not convert the only
occurrence of the corresponding Kconfig macro. Convert that macro now.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/net2272.c

@@ -59,7 +59,7 @@ static const char * const ep_name[] = {
 };
 
 #define DMA_ADDR_INVALID	(~(dma_addr_t)0)
-#ifdef CONFIG_USB_GADGET_NET2272_DMA
+#ifdef CONFIG_USB_NET2272_DMA
 /*
  * use_dma: the NET2272 can use an external DMA controller.
  * Note that since there is no generic DMA api, some functions,