i2c: Add support for custom probe function

The probe method used by i2c_new_probed_device() may not be suitable
for all cases. Let the caller provide its own, optional probe
function.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/i2c/instantiating-devices b/Documentation/i2c/instantiating-devices
index e894902..87da405 100644
--- a/Documentation/i2c/instantiating-devices
+++ b/Documentation/i2c/instantiating-devices
@@ -102,7 +102,7 @@
 	memset(&i2c_info, 0, sizeof(struct i2c_board_info));
 	strlcpy(i2c_info.name, "isp1301_pnx", I2C_NAME_SIZE);
 	isp1301_i2c_client = i2c_new_probed_device(i2c_adap, &i2c_info,
-						   normal_i2c);
+						   normal_i2c, NULL);
 	i2c_put_adapter(i2c_adap);
 	(...)
 }