mem: Move eraseIfNullEntry to when holder is updated

The entry should only be tested for deletion when holder is updated.

Change-Id: I5a10b6fa876912709b7467860d43c23c60f38568
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19750
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed