sunbmac: Fix compiler warning

sunbmac uses '__u32' for dma handle while invoking kernel DMA APIs,
instead of using dma_addr_t. This hasn't caused any 'incompatible
pointer type' warning on SPARC because until now dma_addr_t is of
type u32. However, recent changes in SPARC ATU (iommu) enables 64bit
DMA and therefore dma_addr_t becomes of type u64. This makes
'incompatible pointer type' warnings inevitable.

e.g.
drivers/net/ethernet/sun/sunbmac.c: In function ‘bigmac_ether_init’:
drivers/net/ethernet/sun/sunbmac.c:1166: warning: passing argument 3 of ‘dma_alloc_coherent’ from incompatible pointer type
./include/linux/dma-mapping.h:445: note: expected ‘dma_addr_t *’ but argument is of type ‘__u32 *’

This patch resolves above compiler warning.

Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Reviewed-by: chris hyser <chris.hyser@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>