um: get rid of pointless include "..." where include <...> will do

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/arch/um/drivers/harddog_user.c b/arch/um/drivers/harddog_user.c
index 0345d62..f99b32a 100644
--- a/arch/um/drivers/harddog_user.c
+++ b/arch/um/drivers/harddog_user.c
@@ -6,7 +6,7 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <errno.h>
-#include "os.h"
+#include <os.h>
 
 struct dog_data {
 	int stdin;