fbdev: when parsing E-EDID blocks, also use SVD entries

Add parsing of E-EDID SVD entries. In this first version only a few
CEA/EIA-861E modes are implemented, more can be added as needed.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>