Update PCI git tree location for linux-next

[Bjorn Helgaas]

Hi Stephen,

Can you please replace this PCI tree:

  git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git

with this new shared one:

  git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git

The branch names intended for linux-next ("for-linus" and "next") are
staying the same.

Thanks,
  Bjorn