Documentation/gpu: Add simple doc page for DCHUBBUB

Enable the documentation to extract code documentation from dchubbub.h
file.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Harry Wentland <Harry.Wentland@amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -5,6 +5,18 @@ DCN Blocks
 In this section, you will find some extra details about some of the DCN blocks
 and the code documentation when it is automatically generated.
 
+DCHUBBUB
+--------
+
+.. 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
+   :export:
+
+.. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/hubp.h
+   :internal:
+
 HUBP
 ----
 

drivers/gpu/drm/amd/display/dc/inc/hw/dchubbub.h

@@ -26,6 +26,12 @@
 #ifndef __DAL_DCHUBBUB_H__
 #define __DAL_DCHUBBUB_H__
 
+/**
+ * DOC: overview
+ *
+ * There is only one common DCHUBBUB. It contains the common request and return
+ * blocks for the Data Fabric Interface that are not clock/power gated.
+ */
 
 enum dcc_control {
 	dcc_control__256_256_xxx,