fastmodel: Fix hierachical Iris component names.

fastmodel: Fix hierachical Iris component names.

Recent releases of Fast Models structure Iris resources in a hierarchy.
Use the parent resource ID if set to construct the hierachical name of
components when constructing the resource map.

Change-Id: Iafafa26d5aff560c3b2e93894f81f770c0e98079
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/31076
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>