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/da850_am18xxevm_defconfig b/configs/da850_am18xxevm_defconfig
index b41af4d..779d9cf 100644
--- a/configs/da850_am18xxevm_defconfig
+++ b/configs/da850_am18xxevm_defconfig
@@ -14,6 +14,7 @@
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_SYS_EXTRA_OPTIONS="DA850_AM18X_EVM,SYS_I2C_EEPROM_ADDR_LEN=2,SYS_I2C_EEPROM_ADDR=0x50"
 CONFIG_BOOTDELAY=3
+CONFIG_MISC_INIT_R=y
 CONFIG_VERSION_VARIABLE=y
 # CONFIG_DISPLAY_CPUINFO is not set
 # CONFIG_DISPLAY_BOARDINFO is not set