i2c: tegra: protect suspend/resume callbacks with CONFIG_PM_SLEEP

The CONFIG_PM doesn't actually enable any of the PM callbacks, it
only allows to enable CONFIG_PM_SLEEP and CONFIG_PM_RUNTIME.
This means if CONFIG_PM is used to protect system sleep callbacks
then it may end up unreferenced if only runtime PM is enabled.
Hence protecting sleep callbacks with CONFIG_PM_SLEEP.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>