drm/tegra: Changes for v4.5-rc1

This adds support for the version of host1x found on Tegra210 SoCs. It
also makes use of the new atomic suspend/resume functionality to bring
this feature to Tegra.

Other than that it's mostly small fixes and cleanups, with some prep-
work for things that will hopefully get merged for the next release.

* tag 'drm/tegra/for-4.5-rc1' of git://anongit.freedesktop.org/tegra/linux:
  drm/tegra: Advertise DRIVER_ATOMIC
  drm/tegra: Use DRIVER level for IOMMU aperture message
  drm/tegra: checking for IS_ERR() instead of NULL
  drm/tegra: dc: Add missing of_node_put()
  drm/tegra: Implement subsystem-level suspend/resume
  drm/tegra: sor: Remove unnecessary conditional
  drm/tegra: sor: Operate on struct drm_dp_aux *
  drm/tegra: Use drm_gem_object_unreference_unlocked()
  drm/tegra: Don't take dev->struct_mutex in mmap offset ioctl
  drm/tegra: Use unlocked gem unreferencing
  drm/tegra: Use new multi-driver module helpers
  gpu: host1x: Add Tegra210 support
  gpu: host1x: Remove core driver on unregister
  gpu: host1x: Use platform_register/unregister_drivers()