hisi_acc_vfio_pci: adapt to new migration configuration

On new platforms greater than QM_HW_V3, the migration region has been
relocated from the VF to the PF. The VF's own configuration space is
restored to the complete 64KB, and there is no need to divide the
size of the BAR configuration space equally. The driver should be
modified accordingly to adapt to the new hardware device.

On the older hardware platform QM_HW_V3, the live migration configuration
region is placed in the latter 32K portion of the VF's BAR2 configuration
space. On the new hardware platform QM_HW_V4, the live migration
configuration region also exists in the same 32K area immediately following
the VF's BAR2, just like on QM_HW_V3.

However, access to this region is now controlled by hardware. Additionally,
a copy of the live migration configuration region is present in the PF's
BAR2 configuration space. On the new hardware platform QM_HW_V4, when an
older version of the driver is loaded, it behaves like QM_HW_V3 and uses
the configuration region in the VF, ensuring that the live migration
function continues to work normally. When the new version of the driver is
loaded, it directly uses the configuration region in the PF. Meanwhile,
hardware configuration disables the live migration configuration region
in the VF's BAR2: reads return all 0xF values, and writes are silently
ignored.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Reviewed-by: Shameer Kolothum <shameerkolothum@gmail.com>
Link: https://lore.kernel.org/r/20251030015744.131771-3-liulongfang@huawei.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

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