Allow to exclude each of the external programmer drivers from being compiled in

Example make commandline if you want only internal programmers:
make CONFIG_FT2232SPI=no CONFIG_SERPROG=no CONFIG_NIC3COM=no
CONFIG_SATASII=no CONFIG_DRKAISER=no CONFIG_DUMMY=no

Of course, all of the CONFIG_* symbols can be mixed and matched as
needed. CONFIG_FT2232SPI is special because even if it is enabled, make
will check if the headers are available and skip it otherwise.

Corresponding to flashrom svn r724.

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