mesa/main: fixup requirements for GL_PRIMITIVES_GENERATED

mesa/main: fixup requirements for GL_PRIMITIVES_GENERATED

This enum is also allowed by EXT_tessellation_shader, which is supported
on older i965 HW (as opposed to OES_geometry_shader). This was missed
when narrowing this code-path, leading to dEQP regressions.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108868
Fixes: f09d94fbd11 "mesa/main: fix validation of transform-feedback queries"
Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Tested-by: Mark Janes <mark.a.janes@intel.com>