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/theadorable-x86-dfi-bt700_defconfig b/configs/theadorable-x86-dfi-bt700_defconfig
index f3c2c86..7641df9 100644
--- a/configs/theadorable-x86-dfi-bt700_defconfig
+++ b/configs/theadorable-x86-dfi-bt700_defconfig
@@ -16,6 +16,7 @@
 CONFIG_BOOTSTAGE=y
 CONFIG_BOOTSTAGE_REPORT=y
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
+# CONFIG_ARCH_EARLY_INIT_R is not set
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_CPU=y
 # CONFIG_CMD_IMLS is not set