systemc: Remove a redundant call to update() from the kernel object.

The t0Handler runs the scheduler's initPhase function which has a call
to update built into it. There's no reason to call that within one of
the kernel's callbacks as well.

Change-Id: I02c755b7d53f93accdacf8149cc1988d7a6e214c
Reviewed-on: https://gem5-review.googlesource.com/c/12604
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/kernel.cc

@@ -140,9 +140,6 @@ Kernel::startup()
         stopWork();
 
     kernel->status(::sc_core::SC_RUNNING);
-
-    // Run update once before the event queue starts.
-    ::sc_gem5::scheduler.update();
 }
 
 void