refactor(handoff): downgrade error messages

Some APIs, like `transfer_list_check_header`, are used preemptively to
determine if a new TL needs to be initialized. If we validate a TL and
anticipate its contents to be invalid or corrupted, logging these as
error message isn't helpful.

Change-Id: Ic22378828548d48f73aa74d494f110fbd11857f4
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/lib/transfer_list/transfer_list.c b/lib/transfer_list/transfer_list.c
index 3817861..4d4a167 100644
--- a/lib/transfer_list/transfer_list.c
+++ b/lib/transfer_list/transfer_list.c
@@ -176,35 +176,32 @@
 	}
 
 	if (tl->signature != TRANSFER_LIST_SIGNATURE) {
-		ERROR("Bad transfer list signature 0x%x\n", tl->signature);
+		VERBOSE("Bad transfer list signature 0x%x\n", tl->signature);
 		return TL_OPS_NON;
 	}
 
 	if (!tl->max_size) {
-		ERROR("Bad transfer list max size 0x%x\n",
-		      tl->max_size);
+		VERBOSE("Bad transfer list max size 0x%x\n", tl->max_size);
 		return TL_OPS_NON;
 	}
 
 	if (tl->size > tl->max_size) {
-		ERROR("Bad transfer list size 0x%x\n", tl->size);
+		VERBOSE("Bad transfer list size 0x%x\n", tl->size);
 		return TL_OPS_NON;
 	}
 
 	if (tl->hdr_size != sizeof(struct transfer_list_header)) {
-		ERROR("Bad transfer list header size 0x%x\n",
-		      tl->hdr_size);
+		VERBOSE("Bad transfer list header size 0x%x\n", tl->hdr_size);
 		return TL_OPS_NON;
 	}
 
 	if (!transfer_list_verify_checksum(tl)) {
-		ERROR("Bad transfer list checksum 0x%x\n",
-		      tl->checksum);
+		VERBOSE("Bad transfer list checksum 0x%x\n", tl->checksum);
 		return TL_OPS_NON;
 	}
 
 	if (tl->version == 0) {
-		ERROR("Transfer list version is invalid\n");
+		VERBOSE("Transfer list version is invalid\n");
 		return TL_OPS_NON;
 	} else if (tl->version == TRANSFER_LIST_VERSION) {
 		INFO("Transfer list version is valid for all operations\n");