PCI: tegra: Check return value of tegra_pcie_init_controller()

PCI: tegra: Check return value of tegra_pcie_init_controller()

The return value of tegra_pcie_init_controller() must be checked before
PCIe link up check and registering debugfs entries subsequently as it
doesn't make sense to do these when the controller initialization itself
has failed.

Link: https://lore.kernel.org/r/20201203133451.17716-5-vidyas@nvidia.com
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Thierry Reding <treding@nvidia.com>