ASoC: q6apm: add q6apm_get_hw_pointer helper

ASoC: q6apm: add q6apm_get_hw_pointer helper

Implement an helper function in q6apm to be able to read the current
hardware pointer for both read and write buffers.

This should help q6apm-dai to get the hardware pointer consistently
without it doing manual calculation, which could go wrong in some race
conditions.

Fixes: 9b4fe0f1cd79 ("ASoC: qdsp6: audioreach: add q6apm-dai support")
Cc: stable@vger.kernel.org
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://patch.msgid.link/20250314174800.10142-3-srinivas.kandagatla@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>