btrfs: Fix the wrong condition judgment about subset extent map
Previous commit: btrfs: Fix and enhance merge_extent_mapping() to insert
best fitted extent map
is using wrong condition to judgement whether the range is a subset of a
existing extent map.
This may cause bug in btrfs no-holes mode.
This patch will correct the judgment and fix the bug.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>