mm-video-v4l2: test: Add support to write in NV12 format

The test app writes the YUV output in a format that is supported by
must YUV viewers. In addition to this, this change also let the user
configure the app to write the YUV output just as it get it from the
driver in NV12 format.

Change-Id: I599a993f1b1c0eb668c3c2ba8e0a8fbe5c0fd5b7
2 files changed