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/P1025RDB_NAND_defconfig b/configs/P1025RDB_NAND_defconfig
index 01e775c..b2bd4d5 100644
--- a/configs/P1025RDB_NAND_defconfig
+++ b/configs/P1025RDB_NAND_defconfig
@@ -14,6 +14,7 @@
 CONFIG_OF_STDOUT_VIA_ALIAS=y
 CONFIG_BOOTDELAY=10
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_BOARD_EARLY_INIT_R=y
 # CONFIG_SPL_FRAMEWORK is not set
 CONFIG_TPL=y
 CONFIG_TPL_ENV_SUPPORT=y