drm/vmwgfx/vmwgfx_surface: Fix some kernel-doc related issues

drm/vmwgfx/vmwgfx_surface: Fix some kernel-doc related issues

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:55: warning: Function parameter or member 'prime' not described in 'vmw_user_surface'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:55: warning: Function parameter or member 'backup_base' not described in 'vmw_user_surface'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:78: warning: cannot understand function prototype: 'struct vmw_surface_dirty '
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:173: warning: Function parameter or member 'header' not described in 'vmw_surface_dma'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:173: warning: Function parameter or member 'body' not described in 'vmw_surface_dma'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:173: warning: Function parameter or member 'cb' not described in 'vmw_surface_dma'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:173: warning: Function parameter or member 'suffix' not described in 'vmw_surface_dma'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:181: warning: Function parameter or member 'header' not described in 'vmw_surface_define'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:181: warning: Function parameter or member 'body' not described in 'vmw_surface_define'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:189: warning: Function parameter or member 'header' not described in 'vmw_surface_destroy'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:189: warning: Function parameter or member 'body' not described in 'vmw_surface_destroy'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:555: warning: Function parameter or member 'readback' not described in 'vmw_legacy_srf_unbind'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:1067: warning: Function parameter or member 'res' not described in 'vmw_gb_surface_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:1067: warning: Excess function parameter 'srf' description in 'vmw_gb_surface_create'
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c:1067: warning: Excess function parameter 'cmd_space' description in 'vmw_gb_surface_create'

Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Roland Scheidegger <sroland@vmware.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Zack Rusin <zackr@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210115181313.3431493-34-lee.jones@linaro.org