drm/vmwgfx: fix kernel-doc Excess struct member 'base'

Fix a new kernel-doc warning reported by kernel test robot:

vmwgfx_surface.c:55: warning: Excess struct member 'base' description in 'vmw_user_surface'

The other warning is not correct: it is confused by "__counted_by".
Kees has made a separate patch for that.

In -Wall mode, kernel-doc still reports 20 warnings of this nature:
vmwgfx_surface.c:198: warning: No description found for return value of 'vmw_surface_dma_size'
but I am not addressing those.

Signed-off-by: Randy Dunlap <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Cc: Kees Cook <[email protected]>
Cc: Zack Rusin <[email protected]>
Cc: VMware Graphics Reviewers <[email protected]>
Cc: [email protected]
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Thomas Zimmermann <[email protected]>
Signed-off-by: Zack Rusin <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: rddunlap

drivers/gpu/drm/vmwgfx/vmwgfx_surface.c

@@ -44,7 +44,6 @@
  * struct vmw_user_surface - User-space visible surface resource
  *
  * @prime:          The TTM prime object.
- * @base:           The TTM base object handling user-space visibility.
  * @srf:            The surface metadata.
  * @master:         Master of the creating client. Used for security check.
  */