Documentation/gpu: Remove undocumented files from dcn-blockshubbub.h

The dchubbub.h and hubp.h do not have any meaningful documentation; for
this reason, this commit removes those files from the dcn-blocks
documentation.

Cc: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Rodrigo Siqueira

Documentation/gpu/amdgpu/display/dcn-blocks.rst

@@ -11,18 +11,12 @@ DCHUBBUB
 .. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/dchubbub.h
    :doc: overview
 
-.. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/dchubbub.h
-   :internal:
-
 HUBP
 ----
 
 .. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/hubp.h
    :doc: overview
 
-.. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/hubp.h
-   :internal:
-
 DPP
 ---