[Why]
If we're doing backdoor load then do it entirely ourselves without
invoking any of the frontdoor path to avoid potential issues with
outdated tOS.

[How]
Check the load type and don't pass it to base if we don't want it
loaded.
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NHersen Wu <hersenxs.wu@amd.com>
Acked-by: NRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>