net: thunderx: Remove PF soft reset.

In some silicon revisions, the soft reset clobbers PCI config space,
so quit doing the reset.

Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>