hw/rtc/twl92230: Add missing 'break'

Add missing 'break' to fix:

  hw/rtc/twl92230.c: In function ‘menelaus_write’:
  hw/rtc/twl92230.c:713:5: error: label at end of compound statement
    713 |     default:
        |     ^~~~~~~

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20201211154605.511714-1-f4bug@amsat.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
diff --git a/hw/rtc/twl92230.c b/hw/rtc/twl92230.c
index a787bd2..006d75e 100644
--- a/hw/rtc/twl92230.c
+++ b/hw/rtc/twl92230.c
@@ -697,6 +697,7 @@
 #ifdef VERBOSE
         printf("%s: unknown register %02x\n", __func__, addr);
 #endif
+        break;
     }
 }