sim-se: add missing path redirection to mmap createObjectFile

sim-se: add missing path redirection to mmap createObjectFile

The redirection call was mistakenly removed at:
Ide158e69cdff19bc81157e3e9826bcabc2a51140 and that breaks running
cross compiled dynamically linked executables in SE.

JIRA: https://gem5.atlassian.net/browse/GEM5-430

Change-Id: I33419c78fbf183cda0bba98f7035a2b25ebc6fa3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27887
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Tested-by: Gem5 Cloud Project GCB service account <345032938727@cloudbuild.gserviceaccount.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Gabe Black <gabeblack@google.com>