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>

arch/um/os-Linux/sigio.c

@@ -11,11 +11,11 @@
 #include <sched.h>
 #include <signal.h>
 #include <string.h>
-#include "kern_util.h"
-#include "init.h"
-#include "os.h"
-#include "sigio.h"
-#include "um_malloc.h"
+#include <kern_util.h>
+#include <init.h>
+#include <os.h>
+#include <sigio.h>
+#include <um_malloc.h>
 
 /*
  * Protected by sigio_lock(), also used by sigio_cleanup, which is an