Convert CONFIG_ARCH_EARLY_INIT_R to Kconfig

This converts the following to Kconfig:
   CONFIG_ARCH_EARLY_INIT_R

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/mvebu_db-88f8040_defconfig b/configs/mvebu_db-88f8040_defconfig
index 74bcc89..8e99afc 100644
--- a/configs/mvebu_db-88f8040_defconfig
+++ b/configs/mvebu_db-88f8040_defconfig
@@ -9,6 +9,7 @@
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 # CONFIG_DISPLAY_CPUINFO is not set
 # CONFIG_DISPLAY_BOARDINFO is not set
+CONFIG_ARCH_EARLY_INIT_R=y
 CONFIG_HUSH_PARSER=y
 # CONFIG_CMD_IMLS is not set
 # CONFIG_CMD_FLASH is not set