PCI: tegra: Advertise PCIe Advanced Error Reporting (AER) capability

Default root port setting hides AER capability. This patch enables the
advertisement of AER capability by root port.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Thierry Reding <treding@nvidia.com>