LU-9679 osc: use overlapped() consistently.

LU-9679 osc: use overlapped() consistently.

osc_extent_is_overlapped() open-codes exactly the test that
overlapped() performs.
So use overlapped() instead, to make the code more obviously
consistent.

Linux-Commit: 270995b08634 ("lustre: osc: use overlapped()
	consistently.")

Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Mr NeilBrown <neilb@suse.com>
Change-Id: I3a3ed2ee04343a294ae94f205f5d12be98f99bf3
Reviewed-on: https://review.whamcloud.com/37602
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>