arm/dt: msm8974: Update the max corner limit for VDD_CX voltage regulator

Increase the regulator-max-microvolt values for pm8841_s2_corner
and pm8841_s2_corner_ao to match the updated super turbo corner
value.

Corner values have been remapped inside of the RPM.  This has
resulted in the super turbo corner value changing from 6 to 7.
Therefore, set the value of regulator-max-microvolt to the new
super turbo corner value.

Change-Id: I951384c2549acdd15b1d84febf663f3d24dc27e1
Signed-off-by: David Collins <collinsd@codeaurora.org>