mm-video: venc: Don't align chroma on legacy msm7x30 devices

On legacy msm7x30 devices with a 720p max resolution, the alignment
of chroma to 2K for non-camera YUV420SP input causes wrong recording
of 480p video (eg. the video layers are completely disaligned during
playback).

Change-Id: I794bacc2f714a648073b805e8c02bb568d59fc5f