staging: lustre: llite: add LL_LEASE_{RD,WR,UN}LCK

Define new constants LL_LEASE_{RD,WR,UN}LCK for use as the argument to
and return value from the LL_IOC_{GET,SET}_LEASE ioctls. As arguments,
these contants replace the use of F_{RD,WR,UN}LCK from fcntl.h. As
return values they replace the use of FMODE_{READ,WRITE} which are
internal to the Linux kernel source and not under the control of the
Lustre ioctl interface.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5013
Reviewed-on: http://review.whamcloud.com/10233
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>