GitLab

Specifying spispeed=reserved as programmer parameter resulted in
selecting the default SPI speed instead of aborting. Rewrite the logic
to be more readable.

Corresponding to flashrom svn r1949.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>