extcon: int3496: process id-pin first so that we start with the right status

Some other drivers may be waiting for our extcon to show-up, exiting their
probe methods with -EPROBE_DEFER until we show up.

These drivers will typically get the cable state directly after getting
the extcon, this commit changes the int3496 code to wait for the initial
processing of the id-pin to complete before exiting probe() with 0, which
will cause devices waiting on the defered probe to get reprobed.

This fixes a race where the initial work might still be running while other
drivers were already calling extcon_get_state().

Fixes: 2f556bdb ("extcon: int3496: Add Intel INT3496 ACPI ... driver")
Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>