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/kernel/sigio.c

@@ -4,9 +4,9 @@
  */
 
 #include <linux/interrupt.h>
-#include "irq_kern.h"
-#include "os.h"
-#include "sigio.h"
+#include <irq_kern.h>
+#include <os.h>
+#include <sigio.h>
 
 /* Protected by sigio_lock() called from write_sigio_workaround */
 static int sigio_irq_fd = -1;