ixgbe: fix registration order of driver and DCA nofitication

commit f01fc1a82c2ee68726b400fadb156bd623b5f2f1 upstream.

ixgbe_notify_dca cannot be called before driver registration
because it expects driver's klist_devices to be allocated and
initialized. While on it make sure debugfs files are removed
when registration fails.

Signed-off-by: Jakub Kicinski <jakub.kicinski@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: no debugfs support]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>