Only one execution context for the workqueue used for PF and
VFs mailbox communication is incorrect since multiple works are
queued simultaneously by all the VFs and PF link UP messages.
Hence use default number of execution contexts by passing zero
as max_active to alloc_workqueue function. With this fix in place,
modify UP messages also to wait until completion.

Fixes: d424b6c0 ("octeontx2-pf: Enable SRIOV and added VF mbox handling")
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>