hw/nvme: Update the initalization place for the AER queue

hw/nvme: Update the initalization place for the AER queue

This patch updates the initialization place for the AER queue, so it’s
initialized once, at controller initialization, and not every time
controller is enabled.

While the original version works for a non-SR-IOV device, as it’s hard
to interact with the controller if it’s not enabled, the multiple
reinitialization is not necessarily correct.

With the SR/IOV feature enabled a segfault can happen: a VF can have its
controller disabled, while a namespace can still be attached to the
controller through the parent PF. An event generated in such case ends
up on an uninitialized queue.

While it’s an interesting question whether a VF should support AER in
the first place, I don’t think it must be answered today.

Signed-off-by: Łukasz Gieryk <lukasz.gieryk@linux.intel.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>