ehci-pci: Add PCI EHCI controller

This patch adds support for the PI7C9X442SL PCIe EHCI host controller
from Pericom.

Tested at P4080DS eval board from Freescale.

Signed-off-by: Ralf Trübenbach <ralf.truebenbach@men.de>
Cc: Remy Bohmer <linux@bohmer.net>