net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()

txgbe_shutdown() relies on txgbe_dev_shutdown() to initialise
wake by passing it by reference. However, txgbe_dev_shutdown()
doesn't use this parameter at all.

wake is then passed uninitialised by txgbe_dev_shutdown()
to pci_wake_from_d3().

Resolve this problem by:
* Removing the unused parameter from txgbe_dev_shutdown()
* Removing the uninitialised variable wake from txgbe_dev_shutdown()
* Passing false to pci_wake_from_d3() - this assumes that
  although uninitialised wake was in practice false (0).

I'm not sure that this counts as a bug, as I'm not sure that
it manifests in any unwanted behaviour. But in any case, the issue
was introduced by:

  3ce7547e ("net: txgbe: Add build support for txgbe")

Flagged by Smatch as:

  .../txgbe_main.c:486 txgbe_shutdown() error: uninitialized symbol 'wake'.

No functional change intended.
Compile tested only.

Signed-off-by: Simon Horman <horms@kernel.org>
Reviewed-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>