dma: imx-dma: remove cpu_is_xxx by using platform_device_id

It changes the driver to use platform_device_id rather than cpu_is_xxx
to determine the controller type, and updates the platform code
accordingly.

As the result, mach/hardware.h inclusion gets removed from the driver.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Javier Martin <javier.martin@vista-silicon.com>
Cc: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/arch/arm/mach-imx/mm-imx21.c b/arch/arm/mach-imx/mm-imx21.c
index 1c29515..3b97ea6 100644
--- a/arch/arm/mach-imx/mm-imx21.c
+++ b/arch/arm/mach-imx/mm-imx21.c
@@ -90,7 +90,8 @@
 	mxc_register_gpio("imx21-gpio", 5, MX21_GPIO6_BASE_ADDR, SZ_256, MX21_INT_GPIO, 0);
 
 	pinctrl_provide_dummies();
-	imx_add_imx_dma(MX21_DMA_BASE_ADDR, MX21_INT_DMACH0, 0); /* No ERR irq */
+	imx_add_imx_dma("imx21-dma", MX21_DMA_BASE_ADDR,
+			MX21_INT_DMACH0, 0); /* No ERR irq */
 	platform_device_register_simple("imx21-audmux", 0, imx21_audmux_res,
 					ARRAY_SIZE(imx21_audmux_res));
 }