vbe: Allow VBE to disable adding loadables to the FDT

When VBE operates within VPL it does not want the FDT to be changed.
Provide a way to disable this feature.

Move the FIT_IMAGE_TINY condition out of spl_fit_record_loadable() so
that both conditions are together. This makes the code easier to
understand.

Replace the existing fit_loaded member, which is no-longer used.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/vbe_common.c b/boot/vbe_common.c
index 009bbcd..801ab9d 100644
--- a/boot/vbe_common.c
+++ b/boot/vbe_common.c
@@ -208,6 +208,7 @@
 		struct spl_load_info info;
 
 		spl_load_init(&info, h_vbe_load_read, desc, desc->blksz);
+		xpl_set_fdt_update(&info, false);
 		xpl_set_phase(&info, IH_PHASE_U_BOOT);
 		log_debug("doing SPL from %s blksz %lx log2blksz %x area_offset %lx + fdt_size %lx\n",
 			  blk->name, desc->blksz, desc->log2blksz, area_offset, ALIGN(size, 4));