Documentation/gpu: Add entries to amdgpu glossary

Add missing acronyms to the amdgppu glossary.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/1939
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Tales Lelo da Aparecida <tales.aparecida@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Documentation/gpu/amdgpu/amdgpu-glossary.rst

@@ -8,12 +8,19 @@ we have a dedicated glossary for Display Core at
 
 .. glossary::
 
+    active_cu_number
+      The number of CUs that are active on the system.  The number of active
+      CUs may be less than SE * SH * CU depending on the board configuration.
+
     CP
       Command Processor
 
     CPLIB
       Content Protection Library
 
+    CU
+      Compute Unit
+
     DFS
       Digital Frequency Synthesizer
 
@@ -74,6 +81,12 @@ we have a dedicated glossary for Display Core at
     SDMA
       System DMA
 
+    SE
+      Shader Engine
+
+    SH
+      SHader array
+
     SMU
       System Management Unit