Convert CONFIG_ARCH_MISC_INIT to Kconfig

This converts the following to Kconfig:
   CONFIG_ARCH_MISC_INIT

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/Kconfig b/arch/Kconfig
index 0b64e1d..76c690f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -26,6 +26,7 @@
 
 config BLACKFIN
 	bool "Blackfin architecture"
+	select ARCH_MISC_INIT
 
 config M68K
 	bool "M68000 architecture"