Convert mtip32xx from legacy PCI power management to the generic power
management framework.

Previously, mtip32xx used legacy PCI power management, where
mtip_pci_suspend() and mtip_pci_resume() were responsible for both
device-specific things and generic PCI things:

  mtip_pci_suspend
    mtip_block_suspend(dd)              <-- device-specific
    pci_save_state(pdev)                <-- generic PCI
    pci_set_power_state(pdev, pci_choose_state(pdev, state))

  mtip_pci_resume
    pci_set_power_state(PCI_D0)         <-- generic PCI
    pci_restore_state(pdev)             <-- generic PCI
    pcim_enable_device(pdev)            <-- generic PCI
    pci_set_master(pdev)                <-- generic PCI
    mtip_block_resume(dd)               <-- device-specific

With generic power management, the PCI bus PM methods do the generic PCI
things, and the driver needs only the device-specific part, i.e.,

  suspend_devices_and_enter
    dpm_suspend_start(PMSG_SUSPEND)
      pci_pm_suspend                    # PCI bus .suspend() method
        mtip_pci_suspend                # dev->driver->pm->suspend
          mtip_block_suspend            <-- device-specific
    suspend_enter
      dpm_suspend_noirq(PMSG_SUSPEND)
        pci_pm_suspend_noirq            # PCI bus .suspend_noirq() method
          pci_save_state                <-- generic PCI
          pci_prepare_to_sleep          <-- generic PCI
            pci_set_power_state
    ...
    dpm_resume_end(PMSG_RESUME)
      pci_pm_resume                     # PCI bus .resume() method
        pci_restore_standard_config
          pci_set_power_state(PCI_D0)   <-- generic PCI
          pci_restore_state             <-- generic PCI
        mtip_pci_resume                 # dev->driver->pm->resume
          mtip_block_resume             <-- device-specific

[bhelgaas: commit log]

Link: https://lore.kernel.org/r/20210114115423.52414-2-vaibhavgupta40@gmail.comSigned-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211208192449.146076-4-helgaas@kernel.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>