ionic: no fw read when PCI reset failed

If there was a failed attempt to reset the PCI connection,
don't later try to read from PCI as the space is unmapped
and will cause a paging request crash.  When clearing the PCI
setup we can clear the dev_info register pointer, and check
it before using it in the fw_running test.

Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>