Documentation: PCI: Drop recommendation to configure AER Capability

Documentation: PCI: Drop recommendation to configure AER Capability

Since f26e58bf6f54 ("PCI/AER: Enable error reporting when AER is native"),
the PCI core enables PCIe device error reporting for all devices during
enumeration, so drivers don't need to do it.

Remove the recommendation for drivers to configure AER and call
pci_enable_pcie_error_reporting() themselves.

Also remove the suggestion that drivers may change AER mask and severity
registers.  Ownership of these registers is negotiated between the OS and
platform firmware.  If firmware owns these registers, the OS must not
change them.

Link: https://lore.kernel.org/r/20230609222500.1267795-3-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>