PCI/sysfs: Convert legacy I/O and memory attributes to static definitions

PCI/sysfs: Convert legacy I/O and memory attributes to static definitions

Currently, legacy_io and legacy_mem are dynamically allocated and created
by pci_create_legacy_files(), with pci_adjust_legacy_attr() updating the
attributes at runtime on Alpha to rename them and shift the size for sparse
addressing.

Convert to four static const attributes (legacy_io, legacy_io_sparse,
legacy_mem, legacy_mem_sparse) with .is_bin_visible() callbacks that use
pci_legacy_has_sparse() to select the appropriate variant per bus.  The
sizes are compile-time constants and .size is set directly on each
attribute.

Register the groups in pcibus_groups[] under a HAVE_PCI_LEGACY guard so the
driver model handles creation and removal automatically.

Stub out pci_create_legacy_files() and pci_remove_legacy_files() as the
dynamic creation is no longer needed.  Remove the __weak
pci_adjust_legacy_attr(), Alpha's override, and its declaration from both
Alpha and PowerPC asm/pci.h headers.

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/20260508043543.217179-23-kwilczynski@kernel.org