systemc: Stop using the Accellera specific "none" global event object.

That event being available is nonstandard. Define our own static event
for use in that case.

Change-Id: I5e8892bd83cc1984d63949ef3e249755dca0c702
Reviewed-on: https://gem5-review.googlesource.com/c/15296
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
1 file changed