base, sim: Make ByteOrder into a ScopedEnum accessible to Python

base, sim: Make ByteOrder into a ScopedEnum accessible to Python

There is currently no good way of passing a byte order as a Param
since the ByteOrder type is defined in C++. Make this into a generated
ScopedEnum that can be used in Params.

Change-Id: I990f402340c17c4e0799de57df19516ae61794d4
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33174
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabeblack@google.com>