sparc: Remove no-op dma_4v_sync_single_for_cpu and dma_4v_sync_sg_for_cpu

Now sparc uses include/asm-generic/dma-mapping-common.h.
pci_sun4v.c doesn't need to have no-op
dma_4v_sync_single_for_cpu and dma_4v_sync_sg_for_cpu
(dma-mapping-common.h does nothing if sync_{single|sg}_for_cpu
hook is not defined). So we can remove them safely.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Tested-by: Robert Reif <reif@earthlink.net>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
LKML-Reference: <1249872797-1314-6-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>