power_supply: Add VOLTAGE_MAX_LIMIT power supply property

Add power supply property VOLTAGE_MAX_LIMIT in usb_psy to allow
external entities to impose limitation on the maximum USB adapter
output voltage.

Change-Id: I3d05188f11ccd0c47cfca626e528bbe2e30582ae
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>