DMO: use COINIT_MULTITHREADED instead of COINIT_APARTMENTTHREADED

Fixes #14202

All the other CoInitializeEx() calls and now using multithreading, except for
this code which is called in UpdateRects()
See modules/video_output/msw/common.c l286

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/codec/dmo/dmo.c

@@ -368,7 +368,7 @@ static int DecOpen( decoder_t *p_dec )
     WAVEFORMATEX *p_wf = NULL;
 
     /* Initialize OLE/COM */
-    if( FAILED(CoInitializeEx( NULL, COINIT_APARTMENTTHREADED )) )
+    if( FAILED(CoInitializeEx( NULL, COINIT_MULTITHREADED )) )
         vlc_assert_unreachable();
 
     if( LoadDMO( VLC_OBJECT(p_dec), &hmsdmo_dll, &p_dmo, &p_dec->fmt_in, false )
@@ -1397,7 +1397,7 @@ static int EncOpen( vlc_object_t *p_this )
     HINSTANCE hmsdmo_dll = NULL;
 
     /* Initialize OLE/COM */
-    if( FAILED(CoInitializeEx( NULL, COINIT_APARTMENTTHREADED )) )
+    if( FAILED(CoInitializeEx( NULL, COINIT_MULTITHREADED )) )
         vlc_assert_unreachable();
 
     if( LoadDMO( p_this, &hmsdmo_dll, &p_dmo, &p_enc->fmt_out, true )