LU-6142 libcfs: Enforce kernel coding style for libcfs/debug.c

LU-6142 libcfs: Enforce kernel coding style for libcfs/debug.c

This patch enforces Linux kernel coding style for file
libcfs/libcfs/debug.c reported by checkpatch.

Test-Parameters: trivial
Change-Id: I98fb26a3e4d9dde6f620692e485f1709b8257fc0
Signed-off-by: Robert Read <robert.read@intel.com>
Signed-off-by: Jian Yu <jian.yu@intel.com>
Signed-off-by: Arshad Hussain <arshad.super@gmail.com>
Reviewed-on: https://review.whamcloud.com/14105
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>