regulator: max77802: Fix DT binding document reference

The DT binding doc references the max77802 clocks header file which makes
no sense since of course it doesn't contain data related to the regulators.

It's a copy and paste error, so add a reference to the correct header file.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>