e1000: remember node handle
e1000: remember node handle

While netbooting with yaboot, code was failing at
dma-map-out.

Remember my-handle and store for further reference,
which is needed for dma-map-out during close. yaboot for
some reason does not set the current-node while calling
close.

Signed-off-by: Nikunj A Dadhania <e2f4a5db9b4735182a88051d1e7a3599f9eac9db@linux.vnet.ibm.com>

agraf/SLOF,aik/SLOF,qemu/SLOF,open-power-host-os/slof,agraf/SLOF,stefanberger/SLOF-tpm,aik/SLOF,aik/SLOF,qemu/SLOF,stefanberger/SLOF-tpm,stefanberger/SLOF-tpm,qemu/SLOF,agraf/SLOF,agraf/SLOF,open-power-host-os/slof,open-power-host-os/slof,open-power-host-os/slof