LU-6142 tests: Fix style issues for mmap_sanity.c

LU-6142 tests: Fix style issues for mmap_sanity.c

This patch fixes issues reported by checkpatch
for file lustre/tests/mmap_sanity.c

Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.super@gmail.com>
Change-Id: I37a842ef9a193b554c26deb916b9fe9187b79042
Reviewed-on: https://review.whamcloud.com/35902
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>