mem-cache: Add missing StridePrefetcher invalidation

mem-cache: Add missing StridePrefetcher invalidation

A call to the entry's parent's invalidate function was missing.
Since an entry was only invalidated right before being used,
previous behavior was not breaking anything.

Change-Id: Ibbf31a0099600a8f6be70b3426bac9fcd1e5c749
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35696
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>