configs: MediaTek: use OF_SEPARATE instead of OF_EMBED

This patch replace OF_EMBED with OF_SEPARATE of defconfig files of
MediaTek boards because now OF_EMBED is only used for debugging purpose.

Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/mt7623n_bpir2_defconfig b/configs/mt7623n_bpir2_defconfig
index 53ac63e..8cb4907 100644
--- a/configs/mt7623n_bpir2_defconfig
+++ b/configs/mt7623n_bpir2_defconfig
@@ -26,7 +26,7 @@
 CONFIG_CMD_PING=y
 CONFIG_CMD_FAT=y
 CONFIG_CMD_FS_GENERIC=y
-CONFIG_OF_EMBED=y
+CONFIG_OF_SEPARATE=y
 CONFIG_DEFAULT_DEVICE_TREE="mt7623n-bananapi-bpi-r2"
 CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_REGMAP=y
diff --git a/configs/mt7629_rfb_defconfig b/configs/mt7629_rfb_defconfig
index fdd5f57..1da9932 100644
--- a/configs/mt7629_rfb_defconfig
+++ b/configs/mt7629_rfb_defconfig
@@ -29,7 +29,7 @@
 # CONFIG_CMD_NFS is not set
 CONFIG_CMD_PING=y
 # CONFIG_PARTITIONS is not set
-CONFIG_OF_EMBED=y
+CONFIG_OF_SEPARATE=y
 CONFIG_DEFAULT_DEVICE_TREE="mt7629-rfb"
 CONFIG_OF_SPL_REMOVE_PROPS="pinctrl-0 pinctrl-names clock-names interrupt-parent assigned-clocks assigned-clock-parents"
 CONFIG_NET_RANDOM_ETHADDR=y