[PATCH v5] drm/fourcc: document modifier uniqueness requirements

[Simon Ser]

> > The new paragraph below looks good, but this sentence from the end of
> > the paragraph above still needs to be removed:
> > An example is AFBC, where both ARGB and ABGR have the exact same compressed layout.
>
> I think that entire paragraph was meant to be deleted, the replacement
> is the new one below. Otherwise we have 2x the exact same sentence :-)

Err, indeed, sorry about that! Sending a fixed version.