PCI: layerscape: Add power management support for ls1028a

PCI: layerscape: Add power management support for ls1028a

Add PME_Turn_off/PME_TO_Ack handshake sequence for ls1028a platform.

Implemented on top of common dwc dw_pcie_suspend(resume)_noirq()
functions to handle system enter/exit suspend states.

Link: https://lore.kernel.org/r/20230821184815.2167131-4-Frank.Li@nxp.com
Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: Manivannan Sadhasivam <mani@kernel.org>