ASoC: kirkwood: Fix potential NULL dereference

In kirkwood_dma_hw_params() mv_mbus_dram_info() returns NULL if
CONFIG_PLAT_ORION macro is not defined.
Fix this bug by adding NULL check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: bb6a40fc ("ASoC: kirkwood: Fix reference to PCM buffer address")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Link: https://msgid.link/r/20240328173337.21406-1-amishin@t-argos.ruSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/kirkwood/kirkwood-dma.c

@@ -182,6 +182,9 @@ static int kirkwood_dma_hw_params(struct snd_soc_component *component,
 	const struct mbus_dram_target_info *dram = mv_mbus_dram_info();
 	unsigned long addr = substream->runtime->dma_addr;
 
+	if (!dram)
+		return 0;
+
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		kirkwood_dma_conf_mbus_windows(priv->io,
 			KIRKWOOD_PLAYBACK_WIN, addr, dram);