arm: am335x-pdu001: Move from embedded to separate DTB

There is no need for an embedded device tree for this board so let the
build process generate a separate u-boot.dtb file instead.

Signed-off-by: Felix Brack <fb@ltec.ch>
diff --git a/configs/am335x_pdu001_defconfig b/configs/am335x_pdu001_defconfig
index dc8094e..b69cee0 100644
--- a/configs/am335x_pdu001_defconfig
+++ b/configs/am335x_pdu001_defconfig
@@ -32,7 +32,7 @@
 CONFIG_CMD_REGULATOR=y
 CONFIG_OF_CONTROL=y
 CONFIG_SPL_OF_CONTROL=y
-CONFIG_OF_EMBED=y
+CONFIG_OF_SEPARATE=y
 CONFIG_DEFAULT_DEVICE_TREE="am335x-pdu001"
 # CONFIG_NET is not set
 CONFIG_SPL_DM=y