staging: lustre: libcfs: replace LNET_MAX_IOCTL_BUF_LEN with something bigger

The size of LNET_MAX_IOCTL_BUF_LEN restricts the size of
libcfs ioctl to the maximum needs of the LNet layer. Since
libcfs also handles things like debugging we might need
to let user land pass more data to or from the kernel than
what is possible

Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5435
Reviewed-on: http://review.whamcloud.com/11313


Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Johann Lombardi <johann.lombardi@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>