PCI/doc: Convert examples to generic power management

PCI-specific power management (pci_driver.suspend and pci_driver.resume) is
deprecated. Convert sample code to the generic power management framework.

Link: https://lore.kernel.org/r/20220607232946.355987-1-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Documentation: PCI: convert pci-iov-howto.txt to reST

Convert plain text documentation to reStructuredText format and add it to
Sphinx TOC tree. No essential content change.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>