power: qpnp-charger: automatically set vddsafe when loading vddmax

When loading vddmax from battery profiles, also set vddsafe to
the loaded vddmax + 30 mV. This gives the charger some headroom to
do vddmax adjustments.

Change-Id: Id560add14d09fe3b7d09fe2b32edb2825a6f6f2e
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>