videotoolbox: fail early on unsupported iOS releases (closes #15085)
videotoolbox: fail early on unsupported iOS releases (closes #15085)

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc