libsbc: sbc: implement SBC codec

Use the Android Bluetooth SBC encoder and decoder.
The Android Bluetooth SBC is put as external library (libsbc).
sbc.c/sbc.h implement the interface that is compliant with
Zephyr style and can be used by Zephyr's other modules (
like A2DP).

Signed-off-by: Mark Wang <yichang.wang@nxp.com>