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/mmc/sdhci-cadence.c b/drivers/mmc/sdhci-cadence.c
index dc86d10..eca1b3b 100644
--- a/drivers/mmc/sdhci-cadence.c
+++ b/drivers/mmc/sdhci-cadence.c
@@ -6,10 +6,10 @@
  */
 
 #include <common.h>
+#include <dm.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/sizes.h>
-#include <dm/device.h>
 #include <libfdt.h>
 #include <mmc.h>
 #include <sdhci.h>