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/spear600_usbtty_defconfig b/configs/spear600_usbtty_defconfig
index d6d3a78..8cf0a24 100644
--- a/configs/spear600_usbtty_defconfig
+++ b/configs/spear600_usbtty_defconfig
@@ -8,6 +8,7 @@
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyAMA0,115200 mem=128M root=/dev/mtdblock3 rootfstype=jffs2"
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
+CONFIG_MISC_INIT_R=y
 # CONFIG_DISPLAY_BOARDINFO is not set
 # CONFIG_AUTO_COMPLETE is not set
 CONFIG_CMD_IMLS=y