extcon: Add fsa9480 extcon driver

This patch adds extcon driver for Fairchild Semiconductor FSA9480
microUSB switch.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>
Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>