Support setting the Dediprog SF100 SPI voltage

Add a generic voltage parameter parser.
Move tolower_string() from dummyflasher.c to flashrom.c to make it
available everywhere.

Corresponding to flashrom svn r1226.

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