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/MPC832XEMDS_ATM_defconfig b/configs/MPC832XEMDS_ATM_defconfig
index f334fda..92ca91d 100644
--- a/configs/MPC832XEMDS_ATM_defconfig
+++ b/configs/MPC832XEMDS_ATM_defconfig
@@ -6,6 +6,7 @@
 CONFIG_OF_STDOUT_VIA_ALIAS=y
 CONFIG_SYS_EXTRA_OPTIONS="PQ_MDS_PIB=1,PQ_MDS_PIB_ATM=1"
 CONFIG_BOOTDELAY=6
+CONFIG_BOARD_EARLY_INIT_R=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_IMLS=y
 CONFIG_CMD_ASKENV=y