LU-12355 llite: MS_* flags and SB_* flags split

LU-12355 llite: MS_* flags and SB_* flags split

In kernel 4.20 the MS_* flags should only be used for mount
time flags and SB_* flags for checking super_block.s_flags
The MS_* flags have moved to a uapi header

Conflicts:
	lustre/llite/llite_lib.c

Lustre-commit: 72a84970e6d2a2d4b3a35f2ee058511be2fda82e
Lustre-change: https://review.whamcloud.com/35019

Linux-commit: e262e32d6bde0f77fb0c95d977482fc872c51996

Test-Parameters: trivial
Change-Id: Ifd64efb16c7795377ece066d01ae04dc004a13ac
Signed-off-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-on: https://review.whamcloud.com/40379
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>