eldbus: Check return value of _type_size

_type_size could return 0, which would fail in the modulo call next.
Check for 0, and return.

Fixes CID 1039436

src/lib/eldbus/eldbus_message_to_eina_value.c

@@ -87,6 +87,8 @@ _type_offset(char type, unsigned base)
 {
    unsigned size, padding;
    size = _type_size(type);
+   if (size == 0)
+     return base;
    if (!(base % size))
      return base;
    padding = abs(base - size);