[LIB]: Drop the pcounter itself.

The knock-out. The pcounter abstraction is not used any longer in the
kernel.

Not sure whether this should go via netdev tree, but as far as I
remember it was added via this one, and besides Eric thinks that
Andrew shouldn't mind this.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>