In order to generate the ArmPMU's DTB entry, we have to enable recursion from the ArmISA. This commit follows this mailing list entry: https://www.mail-archive.com/gem5-users@gem5.org/msg18401.html Change-Id: I73012755f0f8c8d4d17278793cf16cb1e8b011df Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35555 Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>