This patch fixes an error in the dl2k driver's DMA mapping/unmapping.
The adapter uses the upper 16bits of the DMA address for the buffer
size.  However, this is not masked off when referencing the DMA
address, and can lead to errors by trying to free a DMA address out of
range.

Thanks,
Jon
Signed-off-by: Jon Mason <jdmason@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>