ALSA: sound/soc/at32: Useless NULL test

The test (ssc != NULL) can only be reached if the call to the function
ssc_request, the result of which ssc is assigned, succeeds. Moreover,
two statements assign NULL to ssc just before a return, which is useless
since it is a local variable. So, we suggest to delete the test and
the two assignments.

A simplified version of the semantic match that finds this problem is
as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@bad_null_test@
expression x,E;
@@
x = ssc_request(...)
... when != x = E
* x != NULL
// </smpl>
Signed-off-by: Julien Brunel <brunel@diku.dk>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

sound/soc/at32/playpaq_wm8510.c

@@ -406,7 +406,6 @@ static int __init playpaq_asoc_init(void)
 	ssc = ssc_request(0);
 	if (IS_ERR(ssc)) {
 		ret = PTR_ERR(ssc);
-		ssc = NULL;
 		goto err_ssc;
 	}
 	ssc_p->ssc = ssc;
@@ -477,10 +476,7 @@ static int __init playpaq_asoc_init(void)
 		_gclk0 = NULL;
 	}
 err_gclk0:
-	if (ssc != NULL) {
-		ssc_free(ssc);
-		ssc = NULL;
-	}
+	ssc_free(ssc);
 err_ssc:
 	return ret;
 }