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/include/asm/page.h b/arch/um/include/asm/page.h
index 7cfc3ce..5ff53d9 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -99,7 +99,7 @@
 
 #define __va_space (8*1024*1024)
 
-#include "mem.h"
+#include <mem.h>
 
 /* Cast to unsigned long before casting to void * to avoid a warning from
  * mmap_kmem about cutting a long long down to a void *.  Not sure that