Enable hybrid 1-D/2-D transform coding for highbd setting

This commit enables the hybrid 1-D/2-D transform coding scheme for
high bit-depth setting. It improves the compression performance of
ext-tx experiment by 0.98% for lowres_all set.

Change-Id: Ic27f5037f2c36b095a93b9f15dbae34bdcdf00aa
2 files changed