Camera: Decrease downsample factor for smaller resolution

After image capture, animation takes place with a downsampled
image (by factor 4). Due to downsampling smaller resolution
(QCIF and others) image size for animated thumbnail is going
below the allocated size and it appeared very small.

Fix: For image size of resolution CIF downwards, use downsampling
factor as 2 without affecting performance for other resolution.

Change-Id: I1098fc1a8f6fb880d5c36ebd2eaeec4415c75fe1
CRs-Fixed: 662891