platform/chrome: wilco_ec: convert stream-like files from nonseekable_open -> stream_open

Eliminate the following coccicheck warning:
./drivers/platform/chrome/wilco_ec/telemetry.c:259:1-17: WARNING:
telem_fops: .read() and .write() have stream semantic; safe to change
nonseekable_open -> stream_open.

Reported-by: Abaci Robot <[e-mail]>
Signed-off-by: Yang Li <[e-mail]>
Signed-off-by: Enric Balletbo i Serra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/platform/chrome/wilco_ec/telemetry.c

···
 	sess_data->dev_data = dev_data;
 	sess_data->has_msg = false;
 
-	nonseekable_open(inode, filp);
+	stream_open(inode, filp);
 	filp->private_data = sess_data;
 
 	return 0;