ASoC: Intel: Skylake: Fix potential NULL pointer dereference

Pointer 'mconfig' returned from call to skl_tplg_fe_get_cpr_module() can
be NULL. So check for the valid pointer before dereferencing.
Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Signed-off-by: Guneshwor Singh <guneshwor.o.singh@intel.com>
Acked-By: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/skylake/skl-pcm.c

@@ -355,6 +355,7 @@ static void skl_pcm_close(struct snd_pcm_substream *substream,
 	}
 
 	mconfig = skl_tplg_fe_get_cpr_module(dai, substream->stream);
+	if (mconfig)
 		skl_tplg_d0i3_put(skl, mconfig->d0i3_caps);
 
 	kfree(dma_params);