LU-6142 mdt: Fix style issues for mdt_internal.h

LU-6142 mdt: Fix style issues for mdt_internal.h

This patch fixes issues reported by checkpatch
for both files lustre/mdt/mdt_internal.h

Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I727c59e7b69b57260c1b8b9aacc71e8c3025e0b9
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56481
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>