LU-10483 lustre: replace FMODE_{READ,WRITE} with MDS_* equivs

LU-10483 lustre: replace FMODE_{READ,WRITE} with MDS_* equivs

In file lustre/include/uapi/linux/lustre/lustre_user.h, replace direct
use of FMODE_READ and FMODE_WRITE with MDS_* equivalents.
That will avoid name clashes with the kernel symbols, and avoid
problems if their values ever change.

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I07e77d8d025c5ddb3dc4e085738645e20fb77d0c
Reviewed-on: https://review.whamcloud.com/30824
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>