Move implicit erase out of chip drivers

Flashrom had an implicit erase-on-write for most flash chip and
programmer drivers, but it was not entirely consistent.

Some drivers had their own hand-rolled partial update functionality
which made handling partial updates from generic code impossible.

Move implicit erase out of chip drivers, and kill some dead erase
functions at the same time. A full chip erase is now performed in the
generic code for all flash chips on write, and after that the whole chip
is written.

Corresponding to flashrom svn r1206.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
12 files changed