Codec2: Integrate support for the system-uncached DMA BUF Heap

While not yet upstream, the system-uncached heap has been added
to android12-5.10, so lets enable support for selecting it on
buffers who's usage flags are not set to C2MemoryUsage::CPU_READ
or C2MemoryUsage::CPU_WRITE.

Because it isn't guarenteed to exist, this adds a helper
function to check if system-uncached is supported as well, so
devices without it can fall back to the system heap.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: I525525cae85b6759e460598c454f1e5f150391f9