Fix a code style issue introduced from upstream

Consolidate use statements into one.

Author: kuanchihwang

src/dynamics/mpas/stepon.F90

@@ -72,9 +72,8 @@ end subroutine stepon_run2
     ! Called by `cam_run3` in `src/control/cam_comp.F90`.
     subroutine stepon_run3(dtime_phys, cam_runtime_opts, cam_out, phys_state, dyn_in, dyn_out)
         ! Module(s) from CAM-SIMA.
-        use physics_types, only: cam_out_t
         use dyn_comp, only: dyn_export_t, dyn_import_t, dyn_run
-        use physics_types, only: physics_state
+        use physics_types, only: cam_out_t, physics_state
         use runtime_obj, only: runtime_options
         ! Module(s) from CCPP.
         use ccpp_kinds, only: kind_phys