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>