PCI: endpoint: Make PCI_ENDPOINT depend on HAS_DMA

If NO_DMA=y:

    drivers/built-in.o: In function `__pci_epc_create':
    (.text+0xef4e): undefined reference to `bad_dma_ops'
    drivers/built-in.o: In function `pci_epc_add_epf':
    (.text+0xf676): undefined reference to `bad_dma_ops'
    drivers/built-in.o: In function `pci_epf_alloc_space':
    (.text+0xfa32): undefined reference to `bad_dma_ops'
    drivers/built-in.o: In function `pci_epf_free_space':
    (.text+0xfac4): undefined reference to `bad_dma_ops'

Add a dependency on HAS_DMA to fix this.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>