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/meson_gx_mmc.c b/drivers/mmc/meson_gx_mmc.c
index 2dda1b7..18b072d 100644
--- a/drivers/mmc/meson_gx_mmc.c
+++ b/drivers/mmc/meson_gx_mmc.c
@@ -5,12 +5,12 @@
  */
 
 #include <common.h>
+#include <dm.h>
 #include <fdtdec.h>
 #include <malloc.h>
 #include <mmc.h>
 #include <asm/io.h>
 #include <asm/arch/sd_emmc.h>
-#include <dm/device.h>
 #include <linux/log2.h>
 
 static inline void *get_regbase(const struct mmc *mmc)