ibmvnic: driver initialization for kdump/kexec

ibmvnic: driver initialization for kdump/kexec

When booting into the kdump/kexec kernel, pHyp and vios
are not prepared for the initialization crq request and
a failover transport event is generated. This is not
handled correctly.

At this point in initialization the driver is still in
the 'probing' state and cannot handle a full reset of the
driver as is normally done for a failover transport event.

To correct this we catch driver resets while still in the
'probing' state and return EAGAIN. This results in the
driver tearing down the main crq and calling ibmvnic_init()
again.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>