drm/amd/display: Enable dlg and vba compilation for dcn314

We were not using the VBA and DLG files for DCN314, but the next
sequence of changes for DCN314 will require those files. This commit
adds the necessary files to the Makefile.

Cc: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>