mtk_adsp_ipc_get_data() can return NULL, but the value is not checked
before being used, leading to static analysis warnings.

sound/soc/sof/mediatek/mt8195/mt8195.c:90:32: error: dereference of
NULL ‘0’ [CWE-476] [-Werror=analyzer-null-dereference]

   90 |         spin_lock_irqsave(&priv->sdev->ipc_lock, flags);
      |                            ~~~~^~~~~~

It appears this is not really a possible problem, so remove those checks.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Yaochun Hung <yc.hung@mediatek.com>
Link: https://lore.kernel.org/r/20230731213748.440285-6-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Some of mediatek processors contain
the Tensilica HiFix DSP for audio processing.

The communication between Host CPU and DSP firmware is
taking place using a shared memory area for message passing.

ADSP IPC protocol offers (send/recv) interfaces using
mediatek-mailbox APIs.

We use two mbox channels to implement a request-reply protocol.

Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Signed-off-by: TingHan Shen <tinghan.shen@mediatek.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Curtis Malainey <cujomalainey@chromium.org>
Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
Reviewed-by: YC Hung <yc.hung@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220512082215.3018-2-tinghan.shen@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>