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/storage/SConscript

@@ -44,7 +44,7 @@ if env['TARGET_ISA'] == 'null':
     Return()
 
 # Controllers
-SimObject('Ide.py')
+SimObject('Ide.py', sim_objects=['IdeDisk', 'IdeController'], enums=['IdeID'])
 
 Source('ide_ctrl.cc')
 Source('ide_disk.cc')
@@ -53,8 +53,9 @@ DebugFlag('IdeCtrl')
 DebugFlag('IdeDisk')
 
 # Disk models
-SimObject('DiskImage.py')
-SimObject('SimpleDisk.py')
+SimObject('DiskImage.py', sim_objects=[
+    'DiskImage', 'RawDiskImage', 'CowDiskImage'])
+SimObject('SimpleDisk.py', sim_objects=['SimpleDisk'])
 
 Source('disk_image.cc')
 Source('simple_disk.cc')