[Qemu-ppc] [PATCHv2 0/8] pseries: Fix and extend PAPR RTC implementation

[David Gibson]

At the moment, the PAPR RTC implementation (actually a paravirt
firmware interface, rather than a normal device) works directly off
host time, and so doesn't respect the options such as clock=vm which
can be specified in the -rtc command line option.

Extending the PAPR RTC in this way makes it clearer it should probably
be its own separate qdev, so this series also implements that.

Finally it moves the code from mc146818rtc for publishing the RTC time
via QOM into generic QOM helpers, and extends the PAPR RTC driver to
export in a similar way.

I've done some basic sanity testing on this, but not much.  In
particular I haven't tested the migration code much yet, so that might
need revision still.

Changes since v1:
  * Actually create a qdev device for the PAPR RTC
  * Instead of duplicating the QOM publishing code from mc146818, move
    it into a generic helper