PCI/IOV: Improve performance of creating VFs concurrently

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9J08D



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Previous commit 700a05bd ("PCI/IOV: Add pci_sriov_numvfs_lock
to support enable pci sriov concurrently")
reduce performance of creating VFs belongs to different PFs.
Fix it by checking whether a new bus will be created.

Fixes: 700a05bd ("PCI/IOV: Add pci_sriov_numvfs_lock to support enable pci sriov concurrently")
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>