dm: Use dm.h header when driver mode is used

This header includes things that are needed to make driver build. Adjust
existing users to include that always, even if other dm/ includes are
present

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/clk/clk_fixed_rate.c b/drivers/clk/clk_fixed_rate.c
index 3911bf6..1cac4bb 100644
--- a/drivers/clk/clk_fixed_rate.c
+++ b/drivers/clk/clk_fixed_rate.c
@@ -6,7 +6,7 @@
 
 #include <common.h>
 #include <clk-uclass.h>
-#include <dm/device.h>
+#include <dm.h>
 
 DECLARE_GLOBAL_DATA_PTR;