systemc: Make suppress_id work like the test expects.

systemc: Make suppress_id work like the test expects.

This is in contrast to how Accellera actually implements it, implying
they would fail their own test.

The specific difference is that suppress_id should only suppress
SC_INFO and SC_WARNING, not all severity levels like the Accellera
implementation will do.

Change-Id: I34f0d2d5912548963433a785cfa6ef88ad818042
Reviewed-on: https://gem5-review.googlesource.com/c/13320
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>