alpha: remove unneeded semicolon in osf_sys.c

Fix the following coccicheck warning:

arch/alpha/kernel/osf_sys.c:680:2-3: Unneeded semicolon

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>
diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index 94e4cde..d5367a1 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -677,7 +677,7 @@
 	default:
 		error = -EOPNOTSUPP;
 		break;
-	};
+	}
 	return error;
 }