i965: Remove unnecessary brw->tess_ctrl_program assertions.

i965: Remove unnecessary brw->tess_ctrl_program assertions.

This is trying to enforce the fact that the hardware requires HS, TE,
and DS to be enabled or disabled together.  But it's kind of an ad-hoc
attempt, and not too useful.

More importantly, we aren't going to have a gl_shader_program for the
TCS which is automatically generated when none is present.  (We'll just
handle it in the driver backend.)  So, these will trip for no reason.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>