UBUNTU: SAUCE: net: hns3: Fix for VF mailbox cannot receiving PF response

UBUNTU: SAUCE: net: hns3: Fix for VF mailbox cannot receiving PF response

BugLink: https://bugs.launchpad.net/bugs/1768670
When the VF frequently switches the CMDQ interrupt, if the CMDQ_SRC is not
cleared, the VF will not receive the new PF response after the interrupt
is re-enabled, the corresponding log is as follows:

[  317.482222] hns3 0000:00:03.0: VF could not get mbx resp(=0) from PF
in 500 tries
[  317.483137] hns3 0000:00:03.0: VF request to get tqp info from PF
failed -5

This patch fixes this problem by clearing CMDQ_SRC before enabling
interrupt and syncing pending IRQ handlers after disabling interrupt.

Fixes: e2cb1dec9779 ("net: hns3: Add HNS3 VF HCL(Hardware Compatibility Layer) Support")
Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>