ASoC: imx-hdmi-dma: Whitspace cosmetics
ASoC: imx-hdmi-dma: Fix subframe assembly / channel status in HBR mode.

High bitrate mode is siganlled to the driver as passthrough with 8 channels.
However, it is infact a two channel mode. This patch corrects the handling
of priv->frame_idx to create proper channel status information.