Revert "spapr: support memory unplug for qtest"

Revert "spapr: support memory unplug for qtest"

Commit b8165118f52c broke CPU hotplug tests for old machine types:

$ QTEST_QEMU_BINARY=ppc64-softmmu/qemu-system-ppc64 ./tests/cpu-plug-test -m=slow
/ppc64/cpu-plug/pseries-3.1/device-add/2x3x1&maxcpus=6: OK
/ppc64/cpu-plug/pseries-2.12-sxxm/device-add/2x3x1&maxcpus=6: OK
/ppc64/cpu-plug/pseries-3.0/device-add/2x3x1&maxcpus=6: OK
/ppc64/cpu-plug/pseries-2.10/device-add/2x3x1&maxcpus=6: OK
/ppc64/cpu-plug/pseries-2.11/device-add/2x3x1&maxcpus=6: OK
/ppc64/cpu-plug/pseries-2.12/device-add/2x3x1&maxcpus=6: OK
/ppc64/cpu-plug/pseries-2.9/device-add/2x3x1&maxcpus=6: OK
/ppc64/cpu-plug/pseries-2.7/device-add/2x3x1&maxcpus=6: **
ERROR:/home/thuth/devel/qemu/hw/ppc/spapr_events.c:313:rtas_event_log_to_source: assertion failed: (source->enabled)
Broken pipe
/home/thuth/devel/qemu/tests/libqtest.c:143: kill_qemu() detected QEMU death from signal 6 (Aborted) (core dumped)
Aborted (core dumped)

The approach of faking the availability of OV5_HP_EVT causes the
code to assume the hotplug event source is enabled, which is wrong
for older machines.

We've now fixed CAS under qtest with a different approach.  Therefore,
this reverts commit b8165118f52ce5ee88565d3cec83d30374efdc96.

A subsequent patch will address the problem of CAS under qtest from
a different angle.

Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <155146875097.147873.1732264036668112686.stgit@bahia.lan>
Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>