kernel/fork.c: fix coding style issues

Fix errors reported by checkpatch.pl.  One error is parentheses, the other
is a whitespace issue.
Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/fork.c

@@ -1654,7 +1654,7 @@ SYSCALL_DEFINE0(fork)
 	return do_fork(SIGCHLD, 0, 0, NULL, NULL);
 #else
 	/* can not support in nommu mode */
-	return(-EINVAL);
+	return -EINVAL;
 #endif
 }
 #endif