util/disk_cache: Add compression in blob cb path

util/disk_cache: Add compression in blob cb path

Android's implementation of the blob-cache get/put funcs do not
implement any compression.  And the default cache size is rather small,
at 2MB (!!) per app (although I assume everyone patches android to
increase the size limit).

We don't bother compressing the has_key/put_key path, since that path is
only storing a uint32_t.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19387>