firewire: IEEE 1394 (FireWire) support should depend on HAS_DMA

Commit b3d681a4 ("firewire: Use
COMPILE_TEST for build testing") added COMPILE_TEST as an alternative
dependency for the purpose of build testing the firewire core.
However, this bypasses all other implicit dependencies assumed by PCI,
like HAS_DMA.

If NO_DMA=y:

    drivers/built-in.o: In function `fw_iso_buffer_destroy':
    (.text+0x36a096): undefined reference to `dma_unmap_page'
    drivers/built-in.o: In function `fw_iso_buffer_map_dma':
    (.text+0x36a164): undefined reference to `dma_map_page'
    drivers/built-in.o: In function `fw_iso_buffer_map_dma':
    (.text+0x36a172): undefined reference to `dma_mapping_error'
    drivers/built-in.o: In function `sbp2_send_management_orb':
    sbp2.c:(.text+0x36c6b4): undefined reference to `dma_map_single'
    sbp2.c:(.text+0x36c6c8): undefined reference to `dma_mapping_error'
    sbp2.c:(.text+0x36c772): undefined reference to `dma_map_single'
    sbp2.c:(.te...