gav1: Support 444 and 422 for 8bit using libyuv

The android platform includes libyuv and we can use that to support
444 and 422 av1 content using the software decoder. This will enable
444 and 422 support for AVIF images as well.

Bug: 261112792
Change-Id: I2e08fa4b760fcb772a97be6ee62259d8762b2c12
Test: decode images on an oriole device