IB/hfi1: Use evict mmu rb operation

Use the new cache evict operation in the SDMA code.  This allows the cache
to properly coordinate evicts and removes, preventing any race.  With this
change, the separate list, lock, and race flag are not needed.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>