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/sys-ppc/sigcontext.c b/arch/um/sys-ppc/sigcontext.c
index 40694d0..aac6c83 100644
--- a/arch/um/sys-ppc/sigcontext.c
+++ b/arch/um/sys-ppc/sigcontext.c
@@ -1,4 +1,4 @@
 #include "asm/ptrace.h"
 #include "asm/sigcontext.h"
-#include "sysdep/ptrace.h"
+#include <sysdep/ptrace.h>