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/P1021RDB-PC_SPIFLASH_defconfig b/configs/P1021RDB-PC_SPIFLASH_defconfig
index 4e87b312..7df50ae 100644
--- a/configs/P1021RDB-PC_SPIFLASH_defconfig
+++ b/configs/P1021RDB-PC_SPIFLASH_defconfig
@@ -16,6 +16,7 @@
 CONFIG_SYS_EXTRA_OPTIONS="SPIFLASH"
 CONFIG_BOOTDELAY=10
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_BOARD_EARLY_INIT_R=y
 # CONFIG_SPL_FRAMEWORK is not set
 CONFIG_SPL_ENV_SUPPORT=y
 CONFIG_SPL_I2C_SUPPORT=y