power: reset: ltc2952: drop empty suspend/resume functions

Documentation/SubmittingDrivers suggests these be implemented even when
they do nothing. On the other hand, the platform code calls these
functions 'legacy'. Suspend and resume operations should go into a
pm_ops structure, pointed at by the driver's pm field. This approach
would lead to a lot of boiler plate, while achieving nothing. Drop the
functions instead.

Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>