powerpc/pci: Disable filling pci-OF-bus-map for non-chrp/powermac

Creating or filling pci-OF-bus-map property in the device-tree is
deprecated since May 2006 [1] and was used only in old platforms like
PowerMac.

Currently kernel code handles it only for chrp and powermac code. So
completely disable filling pci-OF-bus-map property for non-chrp and
non-powermac platforms.

[1] - https://lore.kernel.org/linuxppc-dev/1148016268.13249.14.camel@localhost.localdomain/

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220706104308.5390-5-pali@kernel.org