PCI: tegra194: Disable L1.2 capability of Tegra234 EP

PCI: tegra194: Disable L1.2 capability of Tegra234 EP

When Tegra234 is operating in the Endpoint mode with L1.2 enabled, PCIe
link goes down during L1.2 exit. This is because Tegra234 powers up UPHY
PLL immediately without making sure that the REFCLK is stable.

This causes UPHY PLL to fail to lock to the correct frequency and leads to
link going down. There is no hardware fix for this, hence do not advertise
the L1.2 capability in the Endpoint mode.

Fixes: a54e19073718 ("PCI: tegra194: Add Tegra234 PCIe support")
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Vidya Sagar <vidyas@nvidia.com>
Link: https://patch.msgid.link/20260324190755.1094879-14-mmaddireddy@nvidia.com