LU-6142 lustre: remove ll_file_*_flag wrappers.

LU-6142 lustre: remove ll_file_*_flag wrappers.

ll_file_{test,set,clear,test_and_set}_flag are simple wrappers around
the various *_bit() functions.  They don't aid readability and the
convention in the kernel is to use the *_bit() functions directly.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I0d50f8936ad9f97882f4771dd3210cc05fe43989
Reviewed-on: https://review.whamcloud.com/40292
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>