[PATCH] x86_64: Check for bad dma address in b44 1GB DMA workaround

Needed for interaction with the nommu code in x86-64 which
will return bad_dma_address if the address exceeds dma_mask.

Cc: netdev@vger.kernel.org
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>