superiotool: Update README with Git repository URL and directory location

Change-Id: I36d980cea5ca9cc67262dba809441091757e1fb5
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: http://review.coreboot.org/3019
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
1 file changed