ufs: Drop dm.h header file

This header file should not be included in other header files. Remove it
and use a forward declaration instead.

Also drop asm/io.h

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/ufs/cdns-platform.c b/drivers/ufs/cdns-platform.c
index 1a7bb7b..bad1bf7 100644
--- a/drivers/ufs/cdns-platform.c
+++ b/drivers/ufs/cdns-platform.c
@@ -9,6 +9,7 @@
 #include <common.h>
 #include <dm.h>
 #include <ufs.h>
+#include <asm/io.h>
 #include <dm/device_compat.h>
 #include <linux/bitops.h>
 #include <linux/err.h>
diff --git a/drivers/ufs/ufs.c b/drivers/ufs/ufs.c
index 87b4e5f..92b7e9f 100644
--- a/drivers/ufs/ufs.c
+++ b/drivers/ufs/ufs.c
@@ -19,9 +19,10 @@
 #include <malloc.h>
 #include <hexdump.h>
 #include <scsi.h>
+#include <asm/io.h>
+#include <asm/dma-mapping.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
-
 #include <linux/dma-mapping.h>
 
 #include "ufs.h"
diff --git a/drivers/ufs/ufs.h b/drivers/ufs/ufs.h
index e0bde93..069888f 100644
--- a/drivers/ufs/ufs.h
+++ b/drivers/ufs/ufs.h
@@ -2,11 +2,10 @@
 #ifndef __UFS_H
 #define __UFS_H
 
-#include <asm/io.h>
-#include <dm.h>
-
 #include "unipro.h"
 
+struct udevice;
+
 #define UFS_CDB_SIZE	16
 #define UPIU_TRANSACTION_UIC_CMD 0x1F
 #define UIC_CMD_SIZE (sizeof(u32) * 4)