power_supply: Add isp1704 charger detection driver

NXP ISP1704 is Battery Charging Specification 1.0 compliant USB
transceiver. This adds a power supply driver for ISP1704 and
ISP1707 USB transceivers.

Signed-off-by: Heikki Krogerus <ext-heikki.krogerus@nokia.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>