systemc: Update signals before initing processes.
systemc: Update signals before initing processes.

We were supposed to do one update phase before adding all processes
which didn't have dont_initialize() called to the run queue. We were
doing that in the opposite order.

Change-Id: I6dd4108040d455dc78029da029a2eb5e7af819cb
Reviewed-on: https://gem5-review.googlesource.com/c/14915
Reviewed-by: Matthias Jung <2d08bb393b588a7f78bde56e4f99e16f4aa802a1@eit.uni-kl.de>
Maintainer: Gabe Black <5c8aa1266c03186393d9e7b3b4e3b14239af8201@google.com>

gem5/gem5,gem5/gem5,TUD-OS/gem5-dtu,TUD-OS/gem5-dtu,TUD-OS/gem5-dtu,TUD-OS/gem5-dtu,TUD-OS/gem5-dtu,TUD-OS/gem5-dtu,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,TUD-OS/gem5-dtu