advansys: Remove call to dma_cache_sync()

Only required if the dma buffer has been allocated via
dma_alloc_noncoherent(), which this one is not.
With that call removed we can now also compile on ARM.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>