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/rpi_2_defconfig b/configs/rpi_2_defconfig
index 1a50b23..95bb948 100644
--- a/configs/rpi_2_defconfig
+++ b/configs/rpi_2_defconfig
@@ -6,6 +6,7 @@
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_OF_BOARD_SETUP=y
+CONFIG_MISC_INIT_R=y
 # CONFIG_DISPLAY_CPUINFO is not set
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_SYS_PROMPT="U-Boot> "