vbe: Add fixups for a basic set of OS requests

As a starting point, add support for providing random data, if requested
by the OS. Also add ASLR, as a placeholder for now.

Signed-off-by: Simon Glass <sjg@chromium.org>
(fixed up to use uclass_first_device_err() instead)
diff --git a/test/py/tests/test_event_dump.py b/test/py/tests/test_event_dump.py
index bc54149..e63c25d 100644
--- a/test/py/tests/test_event_dump.py
+++ b/test/py/tests/test_event_dump.py
@@ -16,6 +16,7 @@
     out = util.run_and_log(cons, ['scripts/event_dump.py', sandbox])
     expect = '''.*Event type            Id                              Source location
 --------------------  ------------------------------  ------------------------------
+EVT_FT_FIXUP          bootmeth_vbe_ft_fixup           .*boot/vbe_fixup.c:.*
 EVT_FT_FIXUP          bootmeth_vbe_simple_ft_fixup    .*boot/vbe_simple.c:.*
 EVT_MISC_INIT_F       sandbox_misc_init_f             .*arch/sandbox/cpu/start.c:'''
     assert re.match(expect, out, re.MULTILINE) is not None