hw/cxl: fix DC extent capacity tracking

hw/cxl: fix DC extent capacity tracking

Per cxl r3.2 Section 9.13.3.3, extent capacity tracking should include
extents in different states including added, pending, etc.

Before the change, for the in-device extent number tracking purpose, we only
have "total_extent_count" defined, which only tracks the number of
extents accepted. However, we need to track number of extents in other
states also, for now it is extents pending-to-add.

To fix that, we introduce a new counter for dynamic capacity
"nr_extents_accepted" which explicitly tracks number of the extents
accepted by the hosts, and fix "total_extent_count" to include
both accepted and pending extents counting.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20250714174509.1984430-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>