UCX: Propagate MPI serialized for all worker creations

Move MPI to UCX thread mode function to common source. Also use
serialized mode for all oshmem initializations.

Signed-off-by: Thomas Vegas <[email protected]>
(cherry picked from commit 44cc663)

Author: tvegas1

ompi/mca/pml/ucx/pml_ucx.c

@@ -288,7 +288,6 @@ int mca_pml_ucx_init(int enable_mpi_threads)
 
     PML_UCX_VERBOSE(1, "mca_pml_ucx_init");
 
-    /* TODO check MPI thread mode */
     params.field_mask  = UCP_WORKER_PARAM_FIELD_THREAD_MODE;
     if (enable_mpi_threads) {
         params.thread_mode = UCS_THREAD_MODE_MULTI;

oshmem/mca/spml/ucx/spml_ucx_component.c

@@ -322,6 +322,8 @@ static int spml_ucx_init(void)
     wkr_params.field_mask  = UCP_WORKER_PARAM_FIELD_THREAD_MODE;
     if (oshmem_mpi_thread_requested == SHMEM_THREAD_MULTIPLE) {
         wkr_params.thread_mode = UCS_THREAD_MODE_MULTI;
+    } else if (oshmem_mpi_thread_requested == SHMEM_THREAD_SERIALIZED) {
+        wkr_params.thread_mode = UCS_THREAD_MODE_SERIALIZED;
     } else {
         wkr_params.thread_mode = UCS_THREAD_MODE_SINGLE;
     }