fastmodel: Adopt the gem5 namespace

Change-Id: I2317a2593fafcce26a30d8d7b900e844daa64714
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52263
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed