soc/tegra: pmc: Add kerneldoc for reboot notifier

Commit 48b7f80 ("soc/tegra: pmc: Embed reboot notifier in PMC
context") added the reboot_notifier structure to the PMC SoC structure
but did not update the kerneldoc accordingly. Add this missing kerneldoc
description to fix this.

Fixes: 48b7f80 ("soc/tegra: pmc: Embed reboot notifier in PMC context")
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Author: jonhunter

drivers/soc/tegra/pmc.c

@@ -437,6 +437,7 @@ struct tegra_pmc_soc {
  * @wake_sw_status_map: Bitmap to hold raw status of wakes without mask
  * @wake_cntrl_level_map: Bitmap to hold wake levels to be programmed in
  *     cntrl register associated with each wake during system suspend.
+ * @reboot_notifier: PMC reboot notifier handler
  * @syscore: syscore suspend/resume callbacks
  */
 struct tegra_pmc {