mesa/st: fix formats required for EXT_texture_norm16

mesa/st: fix formats required for EXT_texture_norm16

Earlier commit did not take in to account that lists required for
rendering and texturing are parsed separately. This commit simply
removes formats added to the other list.

Fixes: de4eb9a3bb9 ("mesa/st: toggle EXT_texture_norm16 based on format support")
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3961>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3961>