autorec: fix the compilation error (value computed is not used)

src/dvr/dvr_autorec.c

@@ -833,7 +833,7 @@ dvr_autorec_init(void)
     HTSMSG_FOREACH(f, l) {
       if((c = htsmsg_get_map_by_field(f)) == NULL)
         continue;
-      (void *)dvr_autorec_create(f->hmf_name, c);
+      (void)dvr_autorec_create(f->hmf_name, c);
     }
     htsmsg_destroy(l);
   }