regulator: rk808: add the description about dvs gpio for rk808
regulator: rk808: add the description about dvs gpio for rk808

add the description about dvs1, dvs2, and add the example.

Signed-off-by: Chris Zhong <83f0f67e3a475ac31423a7deb3ea3845def2c091@rock-chips.com>
Reviewed-by: Doug Anderson <49983c4a76b998672954ed5edf4a62db4a336502@chromium.org>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs