virtio-mem: Use new Resettable framework instead of LegacyReset

virtio-mem: Use new Resettable framework instead of LegacyReset

LegacyReset does not pass ResetType to the reset callback method, which
the new Resettable framework uses. Due to this, virtio-mem cannot use
the new RESET_TYPE_WAKEUP to skip the reset during wake-up from a
suspended state.

This patch adds overrides Resettable interface methods in VirtIOMEMClass
to use the new Resettable framework and replaces
qemu_[un]register_reset() calls with qemu_[un]register_resettable().

Message-ID: <20240904103722.946194-4-jmarcin@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juraj Marcin <jmarcin@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>