vdpa: add new attribute VDPA_ATTR_DEV_MIN_VQ_SIZE

mainline inclusion
from mainline-v5.16-rc1
commit e47be840
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=e47be840e87ea15677bca2043ee7b696ccacf56a



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This attribute advertises the min value of virtqueue size. The value is
1 by default.

Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>
Link: https://lore.kernel.org/r/2bbc417355c4d22298050b1ba887cecfbde3e85d.1635493219.git.wuzongyong@linux.alibaba.com


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