drivers/rtc/rtc-tegra.c: use struct dev_pm_ops for power management

drivers/rtc/rtc-tegra.c: use struct dev_pm_ops for power management

Make the Tegra RTC controller driver define its PM callbacks through a
struct dev_pm_ops object rather than by using legacy PM hooks in struct
platform_driver.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>