sim: Use the new BitUnion templates in serialize.hh.

serialize.hh should not reference internal implementation details in
the underlying BitUnion types.

Change-Id: I1ce29243db63801b7788f037fdc54811bdab889c
Reviewed-on: https://gem5-review.googlesource.com/7203
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
1 file changed