GRUB has an user-space program emulator that allows to parse config files
and execute boot entries using the kexec tool. Add a grub2-emu subpackage
to install the emulator.
The subpackage is disabled on ppc64le architecture for now since grub2-emu
fails to build there.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>