r8169: improve a check in rtl_init_one

The check for pci_is_pcie() is redundant here because all
chip versions >=18 are PCIe only anyway. In addition use
dma_set_mask_and_coherent() instead of separate calls to
pci_set_dma_mask() and pci_set_consistent_dma_mask().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>