smbios: add smbios_add_usr_blob_size() helper

it will be used by follow up patch when legacy handling
is moved out into a separate file.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Message-Id: <20240314152302.2324164-10-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/smbios/smbios.c

@@ -1411,6 +1411,14 @@ static bool save_opt_list(size_t *ndest, char ***dest, QemuOpts *opts,
     return true;
 }
 
+static void smbios_add_usr_blob_size(size_t size)
+{
+    if (!usr_blobs_sizes) {
+        usr_blobs_sizes = g_array_new(false, false, sizeof(size_t));
+    }
+    g_array_append_val(usr_blobs_sizes, size);
+}
+
 void smbios_entry_add(QemuOpts *opts, Error **errp)
 {
     const char *val;
@@ -1458,10 +1466,12 @@ void smbios_entry_add(QemuOpts *opts, Error **errp)
             smbios_type4_count++;
         }
 
-        if (!usr_blobs_sizes) {
-            usr_blobs_sizes = g_array_new(false, false, sizeof(size_t));
-        }
-        g_array_append_val(usr_blobs_sizes, size);
+        /*
+         * preserve blob size for legacy mode so it could build its
+         * blobs flavor from 'usr_blobs'
+         */
+        smbios_add_usr_blob_size(size);
+
         usr_blobs_len += size;
         if (size > usr_table_max) {
             usr_table_max = size;