spl: fit: be more verbose when an error occurs when applying the overlays

There are many ways the overlay application can fail.
2 of them are probably the most common:
- the application itself failed. Usually this is comes from an unresolved
  reference
- DTBO not available in FIT (could be because of a typo)

In both case it is good to be more explicit about the error and at least
show which overlay is failing.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index 0245dca..5aeb952 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -113,7 +113,7 @@
 
 	node = fdt_subnode_offset(fit, images, str);
 	if (node < 0) {
-		debug("cannot find image node '%s': %d\n", str, node);
+		pr_err("cannot find image node '%s': %d\n", str, node);
 		return -EINVAL;
 	}
 
@@ -359,8 +359,11 @@
 
 			ret = fdt_overlay_apply_verbose(spl_image->fdt_addr,
 							(void *)image_info.load_addr);
-			if (ret)
+			if (ret) {
+				pr_err("failed to apply DT overlay %s\n",
+				       fit_get_name(fit, node, NULL));
 				break;
+			}
 
 			debug("%s: DT overlay %s applied\n", __func__,
 			      fit_get_name(fit, node, NULL));