ASoC: brcm: Add DSL/PON SoC audio driver

This patch adds Broadcom DSL/PON SoC audio driver
with Whistler I2S block. The SoC supported by this
patch are BCM63158B0,BCM63178 and BCM47622/6755

Signed-off-by: Kevin Li <kevin-ke.li@broadcom.com>
Link: https://lore.kernel.org/r/20200312223242.2843-2-kevin-ke.li@broadcom.com


Signed-off-by: Mark Brown <broonie@kernel.org>