dm: Don't include fdtdec functions when of-platdata is enabled

We cannot access the device tree in this case, so avoid compiling in the
various device-tree helper functions.

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/Makefile

@@ -48,11 +48,10 @@ obj-$(CONFIG_$(SPL_)SHA1) += sha1.o
 obj-$(CONFIG_$(SPL_)SHA256) += sha256.o
 
 obj-$(CONFIG_$(SPL_)OF_LIBFDT) += libfdt/
-ifdef CONFIG_SPL_OF_CONTROL
-obj-$(CONFIG_OF_LIBFDT) += libfdt/
-endif
+ifneq ($(CONFIG_SPL_BUILD)$(CONFIG_SPL_OF_PLATDATA),yy)
 obj-$(CONFIG_$(SPL_)OF_CONTROL) += fdtdec_common.o
 obj-$(CONFIG_$(SPL_)OF_CONTROL) += fdtdec.o
+endif
 
 ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_SPL_YMODEM_SUPPORT) += crc16.o