build: Always build the libfdt python module

Do not rely on CONFIG_SPL_OF_PLATDATA to build the libfdt python module.
If swig is present, this will be build

Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
diff --git a/tools/Makefile b/tools/Makefile
index 5b81dde..a609d05 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -111,7 +111,7 @@
 
 # Build a libfdt Python module if swig is available
 # Use 'sudo apt-get install swig libpython-dev' to enable this
-hostprogs-$(CONFIG_SPL_OF_PLATDATA) += \
+hostprogs-y += \
 	$(if $(shell which swig 2> /dev/null),_libfdt.so)
 _libfdt.so-sharedobjs += $(LIBFDT_OBJS)
 libfdt: