extcon: Use the extcon_set_state_sync() instead of deprecated functions

This patch alters the renamed extcon API to set the state of the external
connectors instead of deprecated extcon_set_cable_state_().

Because the patch[1] modifies the function name to maintain the function
naming pattern.
- extcon_set_cable_state_() -> extcon_set_state_sync()
- extcon_get_cable_state_() -> extcon_get_state()

[1] https://lkml.org/lkml/2016/8/4/729


- extcon: Rename the extcon_set/get_state() to maintain the function naming pattern

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Roger Quadros <rogerq@ti.com>