Unify the YUV_420_888 as NV21 in emulator HALs.

Historically, our HAL treats format YUV_420_888 differently for
Camera (NV21) and non-Camera(YV12). This introduced code
complexity/workaround and issues such as displaying black camera
images on emulator if using format as YUV420_888.

Bug: 129974322
Bug: 135953734
Bug: 129973408

Test: CtsCameraTestCases CtsNativeHardwareTestCases
Change-Id: I404344290a918b0925f9c80bd06150e89f8d90a1
6 files changed