extcon: max8997: Avoid forcing UART path on drive probe

Driver unconditionally forces UART path during probe, probably to ensure
that one can get kernel serial log as soon as possible.

This approach causes some issues, especially when board is booted with
non-UART cable connected to micro-USB port. For example, when USB cable is
connected, UART TX/RX lines are unconditionally short-circuited to USB
D+/D- lines. This is in turn recognized by a series of serial BREAK
signals and some random characters when USB host tries to perform
enumeration procedure.

To solve the above issue and keep UART console operational as early as
possible, set UART path only when USB ID reports UART capable cable.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>