fdt: Swap the signature for board_fdt_blob_setup()

This returns a devicetree and updates a parameter with an error code.
Swap it, since this fits better with the way U-Boot normally works. It
also (more easily) allows leaving the existing pointer unchanged.

No yaks were harmed in this change, but there is a very small code-size
reduction.

For sifive, the OF_BOARD option must be set for the function to be
called, so there is no point in checking it again. Also OF_SEPARATE is
defined always.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Matthias Brugger <mbrugger@suse.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
[trini: Update total_compute]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/Marvell/octeontx2/board-fdt.c b/board/Marvell/octeontx2/board-fdt.c
index 04be9fb..e5a4db0 100644
--- a/board/Marvell/octeontx2/board-fdt.c
+++ b/board/Marvell/octeontx2/board-fdt.c
@@ -210,13 +210,9 @@
 	return 0;
 }
 
-/**
- * Return the FDT base address that was passed by ATF
- *
- * Return:	FDT base address received from ATF in x1 register
- */
-void *board_fdt_blob_setup(int *err)
+int board_fdt_blob_setup(void **fdtp)
 {
-	*err = 0;
-	return (void *)fdt_base_addr;
+	*fdtp = (void *)fdt_base_addr;
+
+	return 0;
 }