[colord] cd_edid_parse_string uses only the first 12 bytes

[Florian Höch]

Hi Richard,

I noticed colord is just using the first 12 bytes of EDID strings
(cd-edid.c, in cd_edid_parse_string) while the spec allows up to 13,
which in some cases can lead to (e.g.) truncated ASCII serial. Is this
worth fixing, or would it cause problems with existing things (profile
to device mapping comes to mind)?
(Basically I have some EDID parsing code of my own which I'd like to
match what colord is doing, so another thing that I could do is simply
also truncate to 12 bytes if fixing this in colord would cause headaches)

Florian