LU-6142 lustre: use BIT() macro where appropriate

LU-6142 lustre: use BIT() macro where appropriate

When accessing a bit in a bitmap/mask/flags-word it can be more
readable to use BIT(num) rather than "1 << num".

This patch makes that change to various places in lustre

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I9f10e7e11e0f310c46c9b216f138799c62308279
Reviewed-on: https://review.whamcloud.com/38377
Reviewed-by: Olaf Faaland-LLNL <faaland1@llnl.gov>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Gian-Carlo DeFazio <defazio1@llnl.gov>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>