ARM: mxs: Change duart device to use amba-pl011

The mxs duart is actually an amba-pl011 device. This commit changes
the duart device code to dynamically allocate amba-pl011 device,
so that drivers/serial/amba-pl011.c can be used on mxs.

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-mxs/devices-mx23.h b/arch/arm/mach-mxs/devices-mx23.h
index d0f49fc..1256788 100644
--- a/arch/arm/mach-mxs/devices-mx23.h
+++ b/arch/arm/mach-mxs/devices-mx23.h
@@ -11,6 +11,6 @@
 #include <mach/mx23.h>
 #include <mach/devices-common.h>
 
-extern const struct mxs_duart_data mx23_duart_data __initconst;
+extern const struct amba_device mx23_duart_device __initconst;
 #define mx23_add_duart() \
-	mxs_add_duart(&mx23_duart_data)
+	mxs_add_duart(&mx23_duart_device)