extcon: max77693: Set default uart/usb path by using platform data

This patch determine default uart/usb path by using platform data.
The MAX77693 MUIC device can possibliy set USB/UART/AUDIO/USB_AUX
/UART_AUX to internal h/w path of MUIC device. So, drvier should
determine default uart/usb path.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>