PCI: tegra194: Fix PM error handling in tegra_pcie_config_ep()

PCI: tegra194: Fix PM error handling in tegra_pcie_config_ep()

pm_runtime_enable() will increase power disable depth.  If
dw_pcie_ep_init() fails, we should use pm_runtime_disable() to balance it
with pm_runtime_enable().

Add missing pm_runtime_disable() for tegra_pcie_config_ep().

Fixes: c57247f940e8 ("PCI: tegra: Add support for PCIe endpoint mode in Tegra194")
Link: https://lore.kernel.org/r/20220602031910.55859-1-linmq006@gmail.com
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Vidya Sagar <vidyas@nvidia.com>