drm/amd/display: Fix wrong reference

We recently introduced a commit that caused a compilation warning
because we tried to print a struct as an unsigned int. This commit
address this issue by adding the missing field.

Fixes: "drm/amd/display: add system info table log"

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>