regulator: fan53555: add support for Silergy SYR82x regulators

Silergy SYR82x regulators share the exact same functionality and register layout
as the Fairchild FAN53555 regulators. Therefore extend the driver to add
support for them.

Both types use the same vendor id in their ID1 register, so it's not possible
to distinguish them automatically.

Similarly, the types also do not match. Type 8 used by the SYR827 and SYR828
start at 712.5mV and increment in 12.5mv steps, while the FAN53555 type 8
starts at 600mV and increments in 10mV steps.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>