ASoC: samsung: Add missing prepare for iis clock of s3c24xx

The s3c_i2sv2_probe() only enabled iis clock.  Missing prepare isn't
probably fatal, because for SoC clocks this is usually no-op, but for
correctness this clock should be prepared.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Arvind Yadav<arvind.yadav.cs@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/samsung/s3c-i2s-v2.c

@@ -637,7 +637,7 @@ int s3c_i2sv2_probe(struct snd_soc_dai *dai,
 		return -ENOENT;
 	}
 
-	clk_enable(i2s->iis_pclk);
+	clk_prepare_enable(i2s->iis_pclk);
 
 	/* Mark ourselves as in TXRX mode so we can run through our cleanup
 	 * process without warnings. */