mediatek: Drop dm.h header file

This header file should not be included in other header files. Remove it
and use a forward declaration instead.
Signed-off-by: NSimon Glass <sjg@chromium.org>

arch/arm/include/asm/arch-mediatek/reset.h

@@ -6,7 +6,7 @@
 #ifndef __MEDIATEK_RESET_H
 #define __MEDIATEK_RESET_H
 
-#include <dm.h>
+struct udevice;
 
 int mediatek_reset_bind(struct udevice *pdev, u32 regofs, u32 num_regs);