ARM: i.MX: Move SOC_IMX1 into 'Device tree only'

This patch moves SOC_IMX1 into 'Device tree only' category and renames
imx1-dt.c to mach-imx1.c to align with the name schema of other
i.MX DT only platforms.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
diff --git a/arch/arm/configs/imx_v4_v5_defconfig b/arch/arm/configs/imx_v4_v5_defconfig
index e70032c..5f013c9f 100644
--- a/arch/arm/configs/imx_v4_v5_defconfig
+++ b/arch/arm/configs/imx_v4_v5_defconfig
@@ -28,6 +28,7 @@
 CONFIG_MACH_IMX27_VISSTRIM_M10=y
 CONFIG_MACH_PCA100=y
 CONFIG_MACH_IMX27_DT=y
+CONFIG_SOC_IMX1=y
 CONFIG_SOC_IMX25=y
 CONFIG_PREEMPT=y
 CONFIG_AEABI=y