anv: fix up dynamic clip emission

anv: fix up dynamic clip emission

There were 2 issues :

   * We were not emitting the clip state when the pipeline changed

   * On Gen7 we did not program the front facing & cull mode dynamic
     values in the clip state

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: c34d8ac26e0a21 ("anv: handle dynamic viewport count")
Closes https://gitlab.freedesktop.org/mesa/mesa/-/issues/3379

Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6265>