ARM: imx: prepare deprecating ARCH_MX1, MACH_MX2, MACH_MX21 and MACH_MX27

MACH_... is reserved for machine support, so use SOC as prefix, not MACH.

This introduces new symbols SOC_IMX1, SOC_IMX21 and SOC_IMX27.  They are
selected by the old symbols for now.  There is no substitute for MACH_MX2
as most usages of MX2 only means MX21 + MX27 but not MX25.

Later the choice about CPU and CPU family should go away and the individual
machines should select the right SOC symbol.  This is a precondition to
support more than one SOC in a single kernel image.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
diff --git a/arch/arm/plat-mxc/Kconfig b/arch/arm/plat-mxc/Kconfig
index 3adad38..d80de4e 100644
--- a/arch/arm/plat-mxc/Kconfig
+++ b/arch/arm/plat-mxc/Kconfig
@@ -8,15 +8,12 @@
 
 config ARCH_MX1
 	bool "MX1-based"
-	select CPU_ARM920T
-	select IMX_HAVE_IOMUX_V1
+	select SOC_IMX1
 	help
 	  This enables support for systems based on the Freescale i.MX1 family
 
 config ARCH_MX2
 	bool "MX2-based"
-	select CPU_ARM926T
-	select IMX_HAVE_IOMUX_V1
 	help
 	  This enables support for systems based on the Freescale i.MX2 family