of: flip CONFIG_SPL_DISABLE_OF_CONTROL into CONFIG_SPL_OF_CONTROL

As we discussed a couple of times, negative CONFIG options make our
life difficult; CONFIG_SYS_NO_FLASH, CONFIG_SYS_DCACHE_OFF, ...
and here is another one.

Now, there are three boards enabling OF_CONTROL on SPL:
 - socfpga_arria5_defconfig
 - socfpga_cyclone5_defconfig
 - socfpga_socrates_defconfig

This commit adds CONFIG_SPL_OF_CONTROL for them and deletes
CONFIG_SPL_DISABLE_OF_CONTROL from the other boards to invert
the logic.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/Makefile b/lib/Makefile
index db7d980..3b6a74b 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -49,7 +49,13 @@
 obj-y += list_sort.o
 endif
 
-ifndef CONFIG_SPL_DISABLE_OF_CONTROL
+ifndef CONFIG_SPL_BUILD
+obj-$(CONFIG_OF_LIBFDT) += libfdt/
+obj-$(CONFIG_OF_CONTROL) += fdtdec_common.o
+obj-$(CONFIG_OF_CONTROL) += fdtdec.o
+endif
+
+ifdef CONFIG_SPL_OF_CONTROL
 obj-$(CONFIG_OF_LIBFDT) += libfdt/
 obj-$(CONFIG_OF_CONTROL) += fdtdec_common.o
 obj-$(CONFIG_OF_CONTROL) += fdtdec.o