usb: gadget: USB_FOTG210_UDC should depend on HAS_DMA

If NO_DMA=y:

drivers/built-in.o: In function `fotg210_start_dma':
drivers/usb/gadget/fotg210-udc.c:354: undefined reference to `dma_map_single'
drivers/usb/gadget/fotg210-udc.c:357: undefined reference to `dma_mapping_error'
drivers/usb/gadget/fotg210-udc.c:362: undefined reference to `dma_sync_single_for_cpu'
drivers/usb/gadget/fotg210-udc.c:376: undefined reference to `dma_unmap_single'

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>