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/hsdk_defconfig b/configs/hsdk_defconfig
index 476ce6a..37f6190 100644
--- a/configs/hsdk_defconfig
+++ b/configs/hsdk_defconfig
@@ -7,6 +7,7 @@
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyS0,115200n8"
 CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_BOARD_EARLY_INIT_R=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="hsdk# "
 CONFIG_CMD_ENV_FLAGS=y