LU-6142 utils: Fix style issues for mkfs_lustre.c

LU-6142 utils: Fix style issues for mkfs_lustre.c

This patch fixes issues reported by checkpatch
for file lustre/utils/mkfs_lustre.c

Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.super@gmail.com>
Change-Id: Ibf5833907b38dc67f84e88e7d2c188c6eb51773e
Reviewed-on: https://review.whamcloud.com/38556
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Ben Evans <beevans@whamcloud.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>