config: Add a system clock command-line option

This patch adds a 'sys_clock' command-line option and use it to assign
clocks to the system during instantiation.

As part of this change, the default clock in the System class is
removed and whenever a system is instantiated a system clock value
must be set. A default value is provided for the command-line option.

The configs and tests are updated accordingly.

1 files changed, 1 insertions, 0 deletions

diff --git a/tests/configs/inorder-timing.py b/tests/configs/inorder-timing.py
index b19014328..30e12f777 100644
--- a/tests/configs/inorder-timing.py
+++ b/tests/configs/inorder-timing.py
@@ -42,6 +42,7 @@ system = System(cpu = cpu,
                 physmem = DDR3_1600_x64(),
                 membus = CoherentBus(),
                 mem_mode = "timing")
+system.clock = '1GHz'
 system.system_port = system.membus.slave
 system.physmem.port = system.membus.master
 # create the interrupt controller