hob: save button from settings called a nonexisting method

The method was removed when the process for saving configuration
in Hob was changed. Replace the call with the right function.

[YOCTO #4793]
Signed-off-by: Cristiana Voicu <cristiana.voicu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>