Convert CONFIG_MISC_INIT_R to Kconfig

This converts the following to Kconfig:
   CONFIG_MISC_INIT_R

Signed-off-by: Adam Ford <aford173@gmail.com>
[trini: Update the defaults logic slightly]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/stm32f429-discovery_defconfig b/configs/stm32f429-discovery_defconfig
index 349474c..a61601f 100644
--- a/configs/stm32f429-discovery_defconfig
+++ b/configs/stm32f429-discovery_defconfig
@@ -10,6 +10,7 @@
 CONFIG_BOOTDELAY=3
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyS0,115200 earlyprintk consoleblank=0 ignore_loglevel"
+CONFIG_MISC_INIT_R=y
 # CONFIG_DISPLAY_CPUINFO is not set
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_BOARD_EARLY_INIT_F=y