apalis-tk1: fix pcie reset for reliable gigabit ethernet operation

apalis-tk1: fix pcie reset for reliable gigabit ethernet operation

It turns out that the current PCIe reset implementation in the PCIe
board init function is not quite working reliably due to PCIe reset
timing violations. Fix this by overriding the
tegra_pcie_board_port_reset() function.

Also allow optionally bringing up the PCIe switch as found on the Apalis
Evaluation board. Note however that the Apalis PCIe port is also left
disabled in the device tree by default.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>