create non-empty arch/x86/include/uapi/asm/ files

patch(1) doesn't create zero-length files, so my kernel didn't compile.

Put something in these files so patch(1) actually creates them.

Cc: David Howells <dhowells@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/include/uapi/asm/hw_breakpoint.h b/arch/x86/include/uapi/asm/hw_breakpoint.h
index e69de29..79a9626 100644
--- a/arch/x86/include/uapi/asm/hw_breakpoint.h
+++ b/arch/x86/include/uapi/asm/hw_breakpoint.h
@@ -0,0 +1 @@
+/* */