[Coverity 1666219] Sizeof not portable in mpeg/es.c

While the program behaves correctly on the current processor architecture, it relies on potentially non-portable assumptions about type sizes.

In Control: The sizeof operator is used on a wrong argument that incidentally has the same size (CWE-467)

 788            }
      
CID 1666219: (#2 of 2): Sizeof not portable (SIZEOF_MISMATCH)
suspicious_sizeof: Passing argument 16UL /* sizeof (seekpoint_t) */ to function vlc_alloc and then casting the return value to seekpoint_t ** is suspicious.
 789            (*pp_title)->seekpoint = vlc_alloc( p_sys->chapters.i_count, sizeof(seekpoint_t) );
 790            if( !(*pp_title)->seekpoint )