osc/rdma: do not set use_memory_registraiton in allocate_state_shared

Currenntly, in function allocate_state_shared,
"module->use_memory_registation" is set to false when all MPI ranks
are on same instances (local_size == global_size).

This is harmful when there is only one btl in use, in which case the selected
btl should determine whether memory registration should be used. For
example, btl/ofi uses memory registration even on same instance.

This is unnecessary when three are two btls in use, in which case
btls that uses memory registration have been excluded in function
ompi_osc_rdma_query_alternate_btls.

Therefore, this commit removes the setting of
    module->use_memory_registration
in allocate_state_shared.

Signed-off-by: Wei Zhang <wzam@amazon.com>

Author: wzamazon

ompi/mca/osc/rdma/osc_rdma_component.c

@@ -605,10 +605,6 @@ static int allocate_state_shared (ompi_osc_rdma_module_t *module, void **base, s
         return allocate_state_single (module, base, size);
     }
 
-    if (local_size == global_size) {
-      module->use_memory_registration = false;
-    }
-
     OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "allocating shared internal state");
 
     local_rank_array_size = sizeof (ompi_osc_rdma_rank_data_t) * RANK_ARRAY_COUNT (module);