virtio_vdpa: setup correct vq size with callbacks get_vq_num_{max,min}

mainline inclusion
from mainline-v5.16-rc1
commit 30a03dfc
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5WXCZ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=30a03dfcbbdac22ade72a38b953e0709fbf35baa



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For the devices which implement the get_vq_num_min callback, the driver
should not negotiate with virtqueue size with the backend vdpa device if
the value returned by get_vq_num_min equals to the value returned by
get_vq_num_max.
This is useful for vdpa devices based on legacy virtio specfication.

Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>
Link: https://lore.kernel.org/r/bc0551cec6c3f3dd9424b678b7c22d882aebab3a.1635493219.git.wuzongyong@linux.alibaba.com


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Pengyuan Zhao <zhaopengyuan@hisilicon.com>