Libreboot's binary blob reduction policy is crystal clear:

If a blob can be avoided, it must be avoided.

The ThinkPad T480 was using Intel's VGA ROM for graphics
initialisation very briefly, before Mate fixed libgfxinit.

Since libgfxinit is fixed, the Intel VGA ROM is obsolete,
so we should not be handling this at all.

Similarly, the Nvidia ROM handling has been removed, because
Mate is hard-disabling that in the coreboot code anyway, since
the Nvidia dGPU didn't work when tested anyway.

Even if it did, Libreboot's blob policy makes it clear
that Intel graphics with native init from coreboot is to
be the preferred option.

Signed-off-by: Leah Rowe <leah@libreboot.org>

This uses the excellent deguard utility, written by
the excellent Mate Kukri.

A few bugs but it mostly works. Documentation to come
shortly, in lbwww.git.

Signed-off-by: Leah Rowe <leah@libreboot.org>