linux-user: remove duplicate break in syscall

likely introduced in 3532fa7402cda16f7b95261b0339c58630051f0b

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 08fbc4d..a25bbff 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -3134,7 +3134,6 @@
         case TARGET_SO_RCVLOWAT:
 		optname = SO_RCVLOWAT;
 		break;
-            break;
         default:
             goto unimplemented;
         }