locks: new helpers - flock_lock_inode_wait and posix_lock_inode_wait

commit 29d01b22 upstream.

Allow callers to pass in an inode instead of a filp.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: "J. Bruce Fields" <bfields@fieldses.org>
Tested-by: "J. Bruce Fields" <bfields@fieldses.org>
Cc: William Dauchy <william@gandi.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>