PCI/sysfs: Remove pci_create_legacy_files() and pci_sysfs_init()

PCI/sysfs: Remove pci_create_legacy_files() and pci_sysfs_init()

Currently, pci_create_legacy_files() and pci_remove_legacy_files() are
no-op stubs.  With legacy attributes now handled by static groups
registered via pcibus_groups[], no call site needs them.

Remove both functions, their declarations, and the call sites in
pci_register_host_bridge(), pci_alloc_child_bus(), and pci_remove_bus().

Remove the pci_sysfs_init() late_initcall and sysfs_initialized.  The
late_initcall originally existed to create all the dynamic PCI sysfs files,
but with both resource and legacy attributes now handled by static groups,
it is no longer needed.

Remove the legacy_io and legacy_mem fields from struct pci_bus which were
used to track the dynamically allocated legacy attributes.

Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Link: https://patch.msgid.link/20260508043543.217179-24-kwilczynski@kernel.org