vfio/mdev: Use sysfs_emit() to instead of sprintf()

Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the
value to be returned to user space.
Signed-off-by: Bo Liu <liubo03@inspur.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230129084117.2384-1-liubo03@inspur.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/mdev/mdev_sysfs.c

@@ -96,7 +96,7 @@ static MDEV_TYPE_ATTR_RO(device_api);
 static ssize_t name_show(struct mdev_type *mtype,
 			 struct mdev_type_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%s\n",
+	return sysfs_emit(buf, "%s\n",
 		mtype->pretty_name ? mtype->pretty_name : mtype->sysfs_name);
 }