Revert "global_data: Drop spl_handoff"

This breaks chromebook_coral which says:

   Video: No video mode configured in FSP!

This reverts commit 2e9313179a846b581c0fc3f6a49e19f3d343efa8.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/clk/rockchip/clk_rk3399.c b/drivers/clk/rockchip/clk_rk3399.c
index 155ea8d..6e87db1 100644
--- a/drivers/clk/rockchip/clk_rk3399.c
+++ b/drivers/clk/rockchip/clk_rk3399.c
@@ -8,7 +8,6 @@
 #include <dm.h>
 #include <dt-structs.h>
 #include <errno.h>
-#include <handoff.h>
 #include <log.h>
 #include <malloc.h>
 #include <mapmem.h>
@@ -1468,7 +1467,7 @@
 	init_clocks = true;
 #elif CONFIG_IS_ENABLED(HANDOFF)
 	if (!(gd->flags & GD_FLG_RELOC)) {
-		if (!handoff_get())
+		if (!(gd->spl_handoff))
 			init_clocks = true;
 	}
 #endif