cfi_flash: Add manufacturer-specific fixups

cfi_flash: Add manufacturer-specific fixups

Run fixups based on the JEDEC manufacturer ID independent of the
command set ID.

This changes current behaviour: Previously, geometry reversal for AMD
chips were done based on the command set ID, while they are now done
based on the JEDEC manufacturer and device ID.

Also add fixup for top-boot Atmel chips. A fixup is needed for
AT49BV6416(T) too, but since u-boot currently only reads the low byte
of the device ID, there's no way to tell it apart from AT49BV642D,
which should not have this fixup. Since AT49BV642D support is
necessary to get ATNGW100 board support into mainline, I've commented
out the fixup for now.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>