i965: Do legacy userclipping in OpenGL ES 1.x contexts.

i965: Do legacy userclipping in OpenGL ES 1.x contexts.

Commit fba4823a disabled user clipping for everything except
compatibility profile.  Core profile and OpenGL ES 2.0+ have all removed
the classic, OpenGL 1.0 user clip planes.  ES 1.x, however, still has
them.

Fixes OpenGL ES 1.1 conformance mustpass.c and userclip.c

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Tested-by: Olivier Berthier <olivierx.berthier@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92639
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92641