arm/dt: pm8941/pm8226/pm8110: increase vddsafe

In order to increase charging accuracy, vddmax must be adjusted in
software. However, the vddmax value is limited by vddsafe.

Increase the vddsafe property in order to give the charger driver
some headroom to adjust the target vddmax.

Change-Id: Id0fa6386c64645ef932b08e55b2d008aee885aa0
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>