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/BSC9132QDS_SPIFLASH_DDRCLK100_defconfig b/configs/BSC9132QDS_SPIFLASH_DDRCLK100_defconfig
index acfb2c3..139e1dd 100644
--- a/configs/BSC9132QDS_SPIFLASH_DDRCLK100_defconfig
+++ b/configs/BSC9132QDS_SPIFLASH_DDRCLK100_defconfig
@@ -9,6 +9,7 @@
 CONFIG_SYS_EXTRA_OPTIONS="SPIFLASH,SYS_CLK_100_DDR_100"
 CONFIG_BOOTDELAY=10
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
+CONFIG_BOARD_EARLY_INIT_R=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_IMLS=y
 CONFIG_CMD_I2C=y