s390x: remove useless cast

This patch is the result of coccinelle script
scripts/coccinelle/typecast.cocci

CC: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/s390x/sclp.c

@@ -426,7 +426,7 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code)
         goto out;
     }
 
-    sclp_c->execute(sclp, (SCCB *)&work_sccb, code);
+    sclp_c->execute(sclp, &work_sccb, code);
 
     cpu_physical_memory_write(sccb, &work_sccb,
                               be16_to_cpu(work_sccb.h.length));