Convert CONFIG_BOARD_POSTCLK_INIT to Kconfig

This converts the following to Kconfig:
   CONFIG_BOARD_POSTCLK_INIT

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 391a77c..06a540d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -869,6 +869,7 @@
 
 config ARCH_MX7ULP
 	bool "NXP MX7ULP"
+	select BOARD_POSTCLK_INIT
 	select CPU_V7A
 	select GPIO_EXTRA_HEADER
 	select MACH_IMX
@@ -894,6 +895,7 @@
 
 config ARCH_MX6
 	bool "Freescale MX6"
+	select BOARD_POSTCLK_INIT
 	select CPU_V7A
 	select GPIO_EXTRA_HEADER
 	select MACH_IMX