net: aquantia: Cleanup pci functions module

net: aquantia: Cleanup pci functions module

BugLink: https://bugs.launchpad.net/bugs/1759303
Driver contained a dead code of maintaining multiple pci port instances.
That will never be used since for each pci function a separate NIC
instance is created.
Simplify this, making pci module only responsible for pci resource
management.
NIC initialization is also simplified accordingly.

Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 23ee07ad3c2fd5adf6e9ef21afb9aec489dc3b4e)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>