LU-16700 pcc: reserve flags for PCC-RO

LU-16700 pcc: reserve flags for PCC-RO

This patch reserves flags for PCC-RO. It also adds wire check /
test for these new flags.

Test-Parameters: trivial
Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: I7086843770d16a6a7d2fd6b6ad3c77d43e04bf3b
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50504
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Feng Lei <flei@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>