Revert "st/mesa: silenced unhanded enum warning in st_glsl_to_tgsi.cpp"

This reverts commit 198c50f487.

This needs to be reverted after commit 017199d2d2 ("mesa: Revert
INTEL_fragment_shader_ordering support")

src/mesa/state_tracker/st_glsl_to_tgsi.cpp

@@ -4072,7 +4072,6 @@ glsl_to_tgsi_visitor::visit(ir_call *ir)
    case ir_intrinsic_generic_atomic_comp_swap:
    case ir_intrinsic_begin_invocation_interlock:
    case ir_intrinsic_end_invocation_interlock:
-   case ir_intrinsic_begin_fragment_shader_ordering:
       unreachable("Invalid intrinsic");
    }
 }