Revert "tegra3_dvfs.c: reduce voltage on all cpu steps bt another -50mv, reduce lp core volages by -25mv"

This reverts commit fa48aca693052983d9776e6dd6c173d331d7b746.
Revert "tegra3_dvfs.c: decrease min limit from 800mV to 600mV. Also decrease all CPU voltages by -25mV"

This reverts commit 661bfc725cd55dc27db1dab8578c3440ad2116eb.