[libdvdread] - fix partial reads in file_read - fixes iso playback on ios (which doesn't use libdvdcss and therefore hits this bug)
[libdvdread] - add patch for fixing partial reads in file_read - also upstreamed for inclusion - patch by karlson2k
Merge pull request #5815 from Memphiz/fixisocrash2

[libdvdread] - fix partial read in file_read