mtd: Handle 29LV800BT

The device id makes u-boot think that this chip needs
cfi_reverse_geometry(), which is not the case.
Add it to jedec_flash, so it is handled properly.

Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>