Merge remote-tracking branch 'bonzini/qdev-props-for-anthony' into staging

* bonzini/qdev-props-for-anthony:
  qdev: drop unnecessary parse/print methods
  qdev: use built-in QOM string parser
  qdev: accept hex properties only if prefixed by 0x
  qdev: accept both strings and integers for PCI addresses
  qom: add generic string parsing/printing
  qapi: add tests for string-based visitors
  qapi: add string-based visitors
  qapi: drop qmp_input_end_optional
  qapi: allow sharing enum implementation across visitors