skge: fix build on 32 bit

The following is needed as well to fix warning/error about shifting a 32 bit
value 32 bits which occurs if building on 32 bit platform caused by conversion
to using dma_addr_t

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>