pyramid: Restrict square preview resolutions from VGA front camera

* Addresses failures in certain apps such as Snapchat.
* Resolves INSTALLER-89

Change-Id: I5f65942cdbebc66c3f0d43095e10f3b451bae9b3
pyramid: Set CAMERA_FRONT_VGA flag
pyramid: fstab: Add misc partition

The misc partition is used for certain recovery actions.
pyramid: overlay: enable eject sdcard