osc-portals4: rename OPAL_ASSEMBLY_ARCH values from OMPI_* to OPAL_*

ompi/mca/osc/portals4/osc_portals4_component.c

@@ -601,7 +601,7 @@ component_select(struct ompi_win_t *win, void **base, size_t size, int disp_unit
 
     module->passive_target_access_epoch = false;
 
-#if OPAL_ASSEMBLY_ARCH == OMPI_AMD64 || OPAL_ASSEMBLY_ARCH == IA32
+#if OPAL_ASSEMBLY_ARCH == OPAL_AMD64 || OPAL_ASSEMBLY_ARCH == OPAL_IA32
     *model = MPI_WIN_UNIFIED;
 #else
     *model = MPI_WIN_SEPARATE;