ASoC: samsung-i2s: Check secondary DAI exists before referencing

In a couple of places the driver is missing a check to ensure there is a
secondary DAI before it de-references the pointer to it, causing a null
pointer de-reference. This patch adds a check to avoid this.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

sound/soc/samsung/i2s.c

@@ -462,7 +462,7 @@ static int i2s_set_sysclk(struct snd_soc_dai *dai,
 		if (dir == SND_SOC_CLOCK_IN)
 			rfs = 0;
 
-		if ((rfs && other->rfs && (other->rfs != rfs)) ||
+		if ((rfs && other && other->rfs && (other->rfs != rfs)) ||
 				(any_active(i2s) &&
 				(((dir == SND_SOC_CLOCK_IN)
 					&& !(mod & MOD_CDCLKCON)) ||
@@ -762,7 +762,8 @@ static void i2s_shutdown(struct snd_pcm_substream *substream,
 	} else {
 		u32 mod = readl(i2s->addr + I2SMOD);
 		i2s->cdclk_out = !(mod & MOD_CDCLKCON);
-		other->cdclk_out = i2s->cdclk_out;
+		if (other)
+			other->cdclk_out = i2s->cdclk_out;
 	}
 	/* Reset any constraint on RFS and BFS */
 	i2s->rfs = 0;