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/P1020UTM-PC_36BIT_defconfig b/configs/P1020UTM-PC_36BIT_defconfig
index d0edb8d..81bc51f 100644
--- a/configs/P1020UTM-PC_36BIT_defconfig
+++ b/configs/P1020UTM-PC_36BIT_defconfig
@@ -10,6 +10,7 @@
 CONFIG_OF_STDOUT_VIA_ALIAS=y
 CONFIG_BOOTDELAY=10
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_BOARD_EARLY_INIT_R=y
 CONFIG_HUSH_PARSER=y
 # CONFIG_AUTO_COMPLETE is not set
 CONFIG_CMD_IMLS=y