usb: dwc3-msm: Assign voltage_max after on charger identification

voltage_max shows the max voltage that the charger can negotiate up
to. Assign voltage_max value accordingly based on charger type.

Change-Id: I7a127e9470de04b79df90dc37f65aa4b0d8195b6
Signed-off-by: Sai Krishna Juturi <jsaikrishna@codeaurora.org>