[HEADERS] One line per header in Kbuild files to reduce conflicts

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/include/linux/sunrpc/Kbuild b/include/linux/sunrpc/Kbuild
index 0d1d768..fb438f1 100644
--- a/include/linux/sunrpc/Kbuild
+++ b/include/linux/sunrpc/Kbuild
@@ -1 +1 @@
-unifdef-y := debug.h
+unifdef-y += debug.h