Although previous implementation returned an error when trying to release
a memzone assigned to an ivshmem device, it stills freed it.
Fixes: cd10c42eb5bc ("mem: fix ivshmem freeing")
Signed-off-by: Mauricio Vasquez B <mauricio.vasquezbernal@studenti.polito.it>
Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>