drivers: tee: improve sysfs interface by using sysfs_emit()

Replace scnprintf() with sysfs_emit() while formatting buffer that is
passed to userspace as per the recommendation in
Documentation/filesystems/sysfs.rst. sysfs _show() callbacks should use
sysfs_emit() or sysfs_emit_at() while returning values to the userspace.
This change does not impact functionality, but aligns with sysfs
interface usage guidelines for the tee driver.

Signed-off-by: Akhilesh Patil <akhilesh@ee.iitb.ac.in>
Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

drivers/tee/optee/core.c

@@ -72,7 +72,7 @@ static ssize_t rpmb_routing_model_show(struct device *dev,
 	else
 		s = "user";
 
-	return scnprintf(buf, PAGE_SIZE, "%s\n", s);
+	return sysfs_emit(buf, "%s\n", s);
 }
 static DEVICE_ATTR_RO(rpmb_routing_model);
 

drivers/tee/tee_core.c

@@ -977,7 +977,7 @@ static ssize_t implementation_id_show(struct device *dev,
 	struct tee_ioctl_version_data vers;
 
 	teedev->desc->ops->get_version(teedev, &vers);
-	return scnprintf(buf, PAGE_SIZE, "%d\n", vers.impl_id);
+	return sysfs_emit(buf, "%d\n", vers.impl_id);
 }
 static DEVICE_ATTR_RO(implementation_id);