staging/lustre/obdclass: remove llog_ioctl.c

Remove the unused function llog_ioctl() and the file
lustre/obdclass/llog_ioctl.c.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>