LU-5435 libcfs: copy out ioctl inline buffer

LU-5435 libcfs: copy out ioctl inline buffer

- libcfs_ioctl_popdata should copy out inline buffers.
- code cleanup for libcfs ioctl handler
- error number fix for obd_ioctl_getdata
- add new function libcfs_ioctl_unpack for upcoming patches

Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Change-Id: I3969e4e96b1dc0c2f6c3e86039b97af5482edc74
Reviewed-on: http://review.whamcloud.com/11313
Tested-by: Jenkins
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Johann Lombardi <johann.lombardi@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>