staging: line6: Remove NULL check before kfree

This patch was generated by the following semantic patch:
// <smpl>
@@ expression E; @@
- if (E != NULL) { kfree(E); }
+ kfree(E);

@@ expression E; @@
- if (E != NULL) { kfree(E); E = NULL; }
+ kfree(E);
+ E = NULL;
// </smpl>

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/line6/pcm.c

@@ -189,8 +189,7 @@ int line6_pcm_stop(struct snd_line6_pcm *line6pcm, int channels)
 		line6pcm->buffer_out = NULL;
 	}
 #if LINE6_BACKUP_MONITOR_SIGNAL
-	if (line6pcm->prev_fbuf != NULL)
-		kfree(line6pcm->prev_fbuf);
+	kfree(line6pcm->prev_fbuf);
 #endif
 
 	return 0;