LU-6142 libcfs: Fix style issues for libcfs_hash.h

LU-6142 libcfs: Fix style issues for libcfs_hash.h

This patch fixes issues reported by checkpatch
for file libcfs/include/libcfs/libcfs_hash.h

Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I0826a6ea530b2e8547d52c4123455b6da3d02b46
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56302
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>