Revert "PCI: create function symlinks in /sys/bus/pci/slots/N/"

This reverts commit 75568f80.

Since they're just a convenience anyway, remove these symlinks since
they're causing duplicate filename errors in the wild.

Acked-by: Alex Chiang <achiang@canonical.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>