sandbox: Remove OF_HOSTFILE

OF_HOSTFILE is used on sandbox configs only.  Although it's pretty
unique and not causing any confusions,  we are better of having simpler
config options for the DTB.

So let's replace that with the existing OF_BOARD.  U-Boot would then
have only three config options for the DTB origin.
- OF_SEPARATE, build separately from U-Boot
- OF_BOARD, board specific way of providing the DTB
- OF_EMBED embedded in the u-boot binary(should not be used in production

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/fdtdec.h b/include/fdtdec.h
index 2398142..6c7ab88 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -1158,8 +1158,10 @@
  * Board-specific FDT initialization. Returns the address to a device tree blob.
  * Called when CONFIG_OF_BOARD is defined, or if CONFIG_OF_SEPARATE is defined
  * and the board implements it.
+ *
+ * @err internal error code if we fail to setup a DTB
  */
-void *board_fdt_blob_setup(void);
+void *board_fdt_blob_setup(int *err);
 
 /*
  * Decode the size of memory