tile/PCI: use pci_scan_root_bus instead pci_scan_bus
tile/PCI: use pci_scan_root_bus instead pci_scan_bus

It will update busn_res accordingly, so we get that for last_busno.

Acked-by: Chris Metcalf <074881f6f5da4d3b5278870ff234d1077ee622c0@tilera.com>
Signed-off-by: Yinghai Lu <0674548f4d596393408a51d6287a76ebba2f42aa@kernel.org>
Signed-off-by: Bjorn Helgaas <f10ec01be0c6b54271af5c550cd257810bdf3268@google.com>
KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas