include/asm-generic/vtime.h: avoid zero-length file

patch(1) can't handle zero-length files - it appears to simply not create
the file, so my powerpc build fails.

Put something in here to make life easier.

Cc: Hugh Dickins <hughd@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-generic/vtime.h b/include/asm-generic/vtime.h
index e69de29..b1a4967 100644
--- a/include/asm-generic/vtime.h
+++ b/include/asm-generic/vtime.h
@@ -0,0 +1 @@
+/* no content, but patch(1) dislikes empty files */