Convert CONFIG_CPU_PXA27X to Kconfig

This converts the following to Kconfig:
   CONFIG_CPU_PXA27X

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 26c96ed..b828b8d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -311,6 +311,10 @@
 	select SYS_CACHE_SHIFT_5
 	imply SYS_ARM_MMU
 
+config CPU_PXA27X
+	bool
+	select CPU_PXA
+
 config CPU_SA1100
 	bool
 	select SYS_CACHE_SHIFT_5
@@ -1767,7 +1771,7 @@
 
 config TARGET_COLIBRI_PXA270
 	bool "Support colibri_pxa270"
-	select CPU_PXA
+	select CPU_PXA27X
 	select GPIO_EXTRA_HEADER
 
 config ARCH_UNIPHIER