This patch fixes and enables rectangular intra transform
sizes for 4:1 partitions (that were turned off before).
4:1 partitions can now use rectangular intra predictions with
2:1 rectangular transform sizes.
BDRATE lowres (single keyframe): -0.612%

Change-Id: I6f062f7c08aae8eeb0a55d31e792c8f7e3f302a2