CFI: support JEDEC flash roms in CFI-flash framework

The following patch adds support for non-CFI flash ROMS, by hooking into the
CFI flash code and using most of its code, as recently discussed here in the
thread "Mixing CFI and non-CFI flashs".

Signed-off-by: Michael Schwingen <michael@schwingen.org>
Signed-off-by: Stefan Roese <sr@denx.de>