arm/mx2: use per-SOC nand device

The previous commit introduced one nand device per SoC.  Use this
directly instead of the compatibility macro that will break for
multi-SoC kernels.  And while at it remove the compatibility macro now
that all in-tree users are fixed.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
diff --git a/arch/arm/mach-mx2/mach-mx21ads.c b/arch/arm/mach-mx2/mach-mx21ads.c
index d5eb806..393bc07 100644
--- a/arch/arm/mach-mx2/mach-mx21ads.c
+++ b/arch/arm/mach-mx2/mach-mx21ads.c
@@ -268,7 +268,7 @@
 	mxc_register_device(&mxc_uart_device3, &uart_pdata);
 	mxc_register_device(&mxc_fb_device, &mx21ads_fb_data);
 	mxc_register_device(&mxc_sdhc_device0, &mx21ads_sdhc_pdata);
-	mxc_register_device(&mxc_nand_device, &mx21ads_nand_board_info);
+	mxc_register_device(&imx21_nand_device, &mx21ads_nand_board_info);
 
 	platform_add_devices(platform_devices, ARRAY_SIZE(platform_devices));
 }