regulator: s2mps11: Add support for disabling S2MPS11 regulators in suspend

The driver supported turning off regulators in suspend only for S2MPS14
device.  However this makes also sense for S2MPS11 and can reduce the
power consumption during suspend to RAM.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>