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/P5020DS_NAND_SECURE_BOOT_defconfig b/configs/P5020DS_NAND_SECURE_BOOT_defconfig
index 81a6c8e..ece3e8f 100644
--- a/configs/P5020DS_NAND_SECURE_BOOT_defconfig
+++ b/configs/P5020DS_NAND_SECURE_BOOT_defconfig
@@ -11,6 +11,7 @@
 CONFIG_SYS_EXTRA_OPTIONS="RAMBOOT_PBL"
 CONFIG_BOOTDELAY=10
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_BOARD_EARLY_INIT_R=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_IMLS=y
 CONFIG_CMD_GREPENV=y