[PATCH] drivers/net/tg3: Use the DMA_{32,64}BIT_MASK constants

This one from my DMA_{32,64}BIT_MASK series did not seem to make it
through to upstream.

Use the DMA_{32,64}BIT_MASK constants from dma-mapping.h when calling
pci_set_dma_mask() or pci_set_consistent_dma_mask()
This patch includes dma-mapping.h explicitly because it caused errors
on some architectures otherwise.
See http://marc.theaimsgroup.com/?t=108001993000001&r=1&w=2 for details

Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>