When Tegra PCIe is in endpoint mode it should be available for root port.
PCIe link up by root port fails if it is in suspend state. So, don't allow
Tegra to suspend when endpoint mode is enabled.

Link: https://lore.kernel.org/r/20210623100525.19944-5-omp@nvidia.comSigned-off-by: NOm Prakash Singh <omp@nvidia.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NVidya Sagar <vidyas@nvidia.com>