chore(gfx): Give example of DisableHWTextureUpload app hint

DefaultPixelFormat app hint on the page has example, but
DisableHWTextureUpload does not.  Add an example usage.

Signed-off-by: Antonios Christidis <[email protected]>

Author: Antonios-C

source/linux/Foundational_Components/Graphics/SGX/SGX_Debug_Info.rst

@@ -103,6 +103,10 @@ textures, rather than transfer queue (using the SGX hardware).
 
 Useful to rule out problems in TQ.
 
+.. code-block:: text
+
+   DisableHWTextureUpload=1
+
 DefaultPixelFormat
 ==================