[media] streamzap: Fix a compilation warning when compiled builtin

drivers/media/rc/streamzap.c: In function ‘streamzap_probe’:
drivers/media/rc/streamzap.c:460:2: warning: statement with no effect

Cc: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/rc/streamzap.c

@@ -73,7 +73,7 @@ MODULE_DEVICE_TABLE(usb, streamzap_table);
 #ifdef CONFIG_IR_RC5_SZ_DECODER_MODULE
 #define load_rc5_sz_decode()    request_module("ir-rc5-sz-decoder")
 #else
-#define load_rc5_sz_decode()    0
+#define load_rc5_sz_decode()    {}
 #endif
 
 enum StreamzapDecoderState {