uio: UIO_DMEM_GENIRQ should depend on HAS_DMA

uio: UIO_DMEM_GENIRQ should depend on HAS_DMA

If NO_DMA=y:

drivers/built-in.o: In function `uio_dmem_genirq_release':
drivers/uio/uio_dmem_genirq.c:95: undefined reference to `dma_free_coherent'
drivers/built-in.o: In function `uio_dmem_genirq_open':
drivers/uio/uio_dmem_genirq.c:61: undefined reference to `dma_alloc_coherent'

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hans J. Koch <hjk@hansjkoch.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>