LU-9679 lustre: remove some "#ifdef CONFIG*" from .c files.

LU-9679 lustre: remove some "#ifdef CONFIG*" from .c files.

It is Linux policy to avoid #ifdef in C files where
convenient - .h files are OK.

This patch defines a few inline functions which differ
depending on CONFIG_LUSTRE_FS_POSIX_ACL, and removes
some #ifdefs from .c files.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I680bcf568d3a09d3768cc992a53671352bd125fd
Reviewed-on: https://review.whamcloud.com/39131
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>