kate: fix memory leak (cid #1048911)

modules/codec/kate.c

@@ -1280,6 +1280,8 @@ static subpicture_t *SetupSimpleKateSPU( decoder_t *p_dec, subpicture_t *p_spu,
     if( !p_spu->p_region )
     {
         msg_Err( p_dec, "cannot allocate SPU region" );
+        if( p_bitmap_region )
+            subpicture_region_Delete( p_bitmap_region );
         decoder_DeleteSubpicture( p_dec, p_spu );
         return NULL;
     }