LU-6485 libcfs: embed kr_data into kkuc_reg

In struct kkuc_reg, the "kr_data" is difficult to be freed
outside of libcfs, then it's better to change it to be
inline data instead of the data pointer.

Change-Id: Iaf5e9fbb9bad2540f51da2c4fd9c4047640d0877
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Reviewed-on: http://review.whamcloud.com/14638
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: frank zago <fzago@cray.com>
Reviewed-by: Robert Read <robert.read@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Henri Doreau <henri.doreau@cea.fr>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>