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

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

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

 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:89: warning: Enum value 'vmw_res_rel_max' not described in enum 'vmw_resource_relocation_type'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:136: warning: Function parameter or member 'func' not described in 'vmw_cmd_entry'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:136: warning: Function parameter or member 'cmd_name' not described in 'vmw_cmd_entry'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:212: warning: Function parameter or member 'res' not described in 'vmw_cmd_ctx_first_setup'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:523: warning: Function parameter or member 'sw_context' not described in 'vmw_resource_relocation_add'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:523: warning: Excess function parameter 'list' description in 'vmw_resource_relocation_add'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:653: warning: Function parameter or member 'p_res' not described in 'vmw_cmd_res_check'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:653: warning: Excess function parameter 'p_val' description in 'vmw_cmd_res_check'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:1716: warning: Function parameter or member 'res' not described in 'vmw_cmd_res_switch_backup'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:1716: warning: Excess function parameter 'val_node' description in 'vmw_cmd_res_switch_backup'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:3757: warning: Function parameter or member 'file_priv' not described in 'vmw_execbuf_fence_commands'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:3757: warning: Function parameter or member 'dev_priv' not described in 'vmw_execbuf_fence_commands'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:3757: warning: Function parameter or member 'p_fence' not described in 'vmw_execbuf_fence_commands'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:3757: warning: Function parameter or member 'p_handle' not described in 'vmw_execbuf_fence_commands'
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c:3954: warning: Function parameter or member 'kernel_commands' not described in 'vmw_execbuf_cmdbuf'

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: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.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/20210115181313.3431493-4-lee.jones@linaro.org