PCI/sysfs: Add stubs for pci_{create,remove}_sysfs_dev_files()

PCI/sysfs: Add stubs for pci_{create,remove}_sysfs_dev_files()

On platforms with HAVE_PCI_MMAP or ARCH_GENERIC_PCI_MMAP_RESOURCE, resource
files are now handled by static attribute groups registered via
pci_dev_groups[].

Stub out the pci_create_sysfs_dev_files() and pci_remove_sysfs_dev_files(),
as the dynamic resource file creation is no longer needed.

Also, simplify pci_sysfs_init() on these platforms to only iterate buses
for legacy attributes creation, skipping the per-device loop.

Move the __weak stubs for pci_create_resource_files() and
pci_remove_resource_files() into the #else branch since only platforms
without HAVE_PCI_MMAP (such as Alpha architecture) still need them.  Guard
the res_attr[] and res_attr_wc[] fields in struct pci_dev the same way.

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/20260508043543.217179-10-kwilczynski@kernel.org