Platform data is not used in tegra-ehci anymore, so remove all
references to it.
Signed-off-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com> Tested-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Felipe Balbi <balbi@ti.com>