extcon: int3496: Add GPIO ACPI mapping table

In order to make GPIO ACPI library stricter prepare users of
gpiod_get_index() to correctly behave when there no mapping is
provided by firmware.

Here we add explicit mapping between _CRS GpioIo() resources and
their names used in the driver.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
diff --git a/Documentation/extcon/intel-int3496.txt b/Documentation/extcon/intel-int3496.txt
index af0b366..8155dbc 100644
--- a/Documentation/extcon/intel-int3496.txt
+++ b/Documentation/extcon/intel-int3496.txt
@@ -20,3 +20,8 @@
 Index 2: The output gpio for muxing of the data pins between the USB host and
          the USB peripheral controller, write 1 to mux to the peripheral
          controller
+
+There is a mapping between indices and GPIO connection IDs as follows
+	id	index 0
+	vbus	index 1
+	mux	index 2