drm/amd/display: Creating a fw boot options bit for an upcoming feature

[Why]
Need a bit for x86 driver to enable a FW boot option for an upcoming
feature.

[How]
Added a bit in dmub_fw_boot_options for an upcoming feature.

Reviewed-by: Jimmy Kizito <jimmy.kizito@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>