hwc: source split: Enable BWC for video with width <= mixer width

Enable BWC for videos with crop and position widths <= mixer width.
Source split was earlier used on split panels only, and BWC was
never enabled (It should at least have been for eligible content).
When source split was enabled for all panels, automatically BWC got
disabled for rotated videos. This change fixes that.

Change-Id: I349e782fb6de515ff42fcb137f02cf27c425da56
1 file changed