Boards: Add general nVidia MCP gpio routine

Turns out that the AMD 8111 datasheet describes this bit of the MCP
perfectly.

Corresponding to flashrom svn r792.

Signed-off-by: Luc Verhaegen <libv@skynet.be>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
1 file changed