scons: Add sim_object and enums arguments to SimObject().

This will explicitly declare what SimObject and Enum types need to be set
up in C++, which will make importing all the SimObject modules during
the setup phase of SCons uneccessary.

Change-Id: Id2d7603daf33b236ceaa0789e2f089f589d34e62
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/49406
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/pci/SConscript

@@ -40,14 +40,16 @@
 
 Import('*')
 
-SimObject('PciDevice.py')
+SimObject('PciDevice.py', sim_objects=[
+    'PciBar', 'PciBarNone', 'PciIoBar', 'PciLegacyIoBar', 'PciMemBar',
+    'PciMemUpperBar', 'PciDevice'])
 Source('device.cc')
 DebugFlag('PciDevice')
 
-SimObject('PciHost.py')
+SimObject('PciHost.py', sim_objects=['PciHost', 'GenericPciHost'])
 Source('host.cc')
 DebugFlag('PciHost')
 
-SimObject('CopyEngine.py')
+SimObject('CopyEngine.py', sim_objects=['CopyEngine'])
 Source('copy_engine.cc')
 DebugFlag('DMACopyEngine')