ARM: imx5: drop option MACH_IMX51_DT

Since i.MX51 becomes DT only now, we can drop option MACH_IMX51_DT and
just use SOC_IMX51 instead.  While at it, rename imx51-dt.c to
mach-imx51.c to align with the name schema of other IMX DT only
platforms.

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 061c168..83d8778 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -694,11 +694,6 @@
 	select HAVE_IMX_SRC
 	select MXC_TZIC
 
-config	SOC_IMX51
-	bool
-	select PINCTRL_IMX51
-	select SOC_IMX5
-
 config	SOC_IMX50
 	bool "i.MX50 support"
 	select PINCTRL_IMX50
@@ -707,9 +702,10 @@
 	help
 	  This enables support for Freescale i.MX50 processor.
 
-config MACH_IMX51_DT
+config SOC_IMX51
 	bool "i.MX51 support"
-	select SOC_IMX51
+	select PINCTRL_IMX51
+	select SOC_IMX5
 	help
 	  This enables support for Freescale i.MX51 processor
 
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index bbe93bb..9d7b46f 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -109,8 +109,8 @@
 endif
 obj-$(CONFIG_SOC_IMX6) += pm-imx6.o
 
-obj-$(CONFIG_MACH_IMX51_DT) += imx51-dt.o
 obj-$(CONFIG_SOC_IMX50) += mach-imx50.o
+obj-$(CONFIG_SOC_IMX51) += mach-imx51.o
 obj-$(CONFIG_SOC_IMX53) += mach-imx53.o
 
 obj-$(CONFIG_SOC_VF610) += clk-vf610.o mach-vf610.o
diff --git a/arch/arm/mach-imx/imx51-dt.c b/arch/arm/mach-imx/mach-imx51.c
similarity index 100%
rename from arch/arm/mach-imx/imx51-dt.c
rename to arch/arm/mach-imx/mach-imx51.c