bootstage: Use debug() for stashing messages

We don't normally want to see these messages. Change them to debug-only.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/bootstage.c b/common/bootstage.c
index 1afdee3..32f4e8b 100644
--- a/common/bootstage.c
+++ b/common/bootstage.c
@@ -409,7 +409,7 @@
 
 	/* Update total data size */
 	hdr->size = ptr - (char *)base;
-	printf("Stashed %d records\n", hdr->count);
+	debug("Stashed %d records\n", hdr->count);
 
 	return 0;
 }
@@ -479,7 +479,7 @@
 
 	/* Mark the records as read */
 	data->rec_count += hdr->count;
-	printf("Unstashed %d records\n", hdr->count);
+	debug("Unstashed %d records\n", hdr->count);
 
 	return 0;
 }