treewide: Migrate CONFIG_BOARD_EARLY_INIT_R to Kconfig

Migrate the CONFIG_BOARD_EARLY_INIT_R option to Kconfig.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/configs/kmcoge4_defconfig b/configs/kmcoge4_defconfig
index 9d22c21..5015585 100644
--- a/configs/kmcoge4_defconfig
+++ b/configs/kmcoge4_defconfig
@@ -9,6 +9,7 @@
 CONFIG_SYS_EXTRA_OPTIONS="KMCOGE4"
 CONFIG_VERSION_VARIABLE=y
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_BOARD_EARLY_INIT_R=y
 CONFIG_HUSH_PARSER=y
 CONFIG_AUTOBOOT_KEYED=y
 CONFIG_AUTOBOOT_PROMPT="Hit <SPACE> key to stop autoboot in %2ds\n"