Loading all_video for EFI can cause video issues in some cases
since GRUB Bochs/Cirrus drivers may conflict with native EFI drivers.
Change default behavior for EFI to only load EFI specific video
modules. Also include a new environment variable to restore the old
behavior if needed.
Fixes: https://savannah.gnu.org/bugs/?66200
Signed-off-by: Andrew Hamilton <adhamilt@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>