microblaze/PCI: Remove unused PCI bus scan if configured as a host

This routine is meant to be used early during boot, when the
PCI bus numbers have not yet been assigned, and you need to
issue PCI config cycles to an OF device.

It could also be used to "fix" RTAS config cycles if you want
to set pci_assign_all_buses to 1 and still use RTAS for PCI
config cycles.

Signed-off-by: Thippeswamy Havalige <thippeswamy.havalige@amd.com>
Link: https://lore.kernel.org/r/20221025065214.4663-4-thippeswamy.havalige@amd.com


Signed-off-by: Michal Simek <michal.simek@amd.com>