Revision 3722

Add additional SPI sector erase and chip erase command functions to
flashrom. Not all chips support all commands, so allow the implementer
to select the matching function.
Fix a layering violation in ICH SPI code to be less bad. Still not
perfect, but the new code is shorter, more generic and
architecturally
more sound.

TODO (in a separate patch):
- move the generic sector erase code to spi.c
- decide which erase command to use based on info about the chip
- create a generic spi_erase_all_sectors function which calls the
generic sector erase function
  
Thanks to Stefan for reviewing and commenting.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Reinauer <stepan@coresystems.de>