vhost: move the backend feature bits to vhost_types.h

mainline inclusion
from mainline-v5.19-rc1
commit 175d493c
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=175d493c3c3e09a3abaa843068fae0f0ad42c47e



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We should store feature bits in vhost_types.h as what has been done
for e.g VHOST_F_LOG_ALL.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Gautam Dawar <gdawar@xilinx.com>
Message-Id: <20220330180436.24644-2-gdawar@xilinx.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Pengyuan Zhao <zhaopengyuan@hisilicon.com>