stdlib: Update the LupvBoard to use 'requires'

Usage of this function was previously avoided due to a bug which has
since been fixed:
https://gem5-review.googlesource.com/c/public/gem5/+/53003

Change-Id: Idc76ca26d02dcfbb290cebcca297e50e905d8e6d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53084
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
1 file changed