Convert from pci_scan_bus() to pci_scan_root_bus() and remove root bus
resource fixups.  This fixes the problem of "early" and "header" quirks
seeing incorrect root bus resources.

CC: Russell King <linux@arm.linux.org.uk>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>