blkid: optional support for TYPE="fstype"

Adapted from patch created by T4ndeta <t4ndeta@gmail.com>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/util-linux/volume_id/fat.c b/util-linux/volume_id/fat.c
index b0f427c..904fbb2 100644
--- a/util-linux/volume_id/fat.c
+++ b/util-linux/volume_id/fat.c
@@ -332,7 +332,7 @@
 
  ret:
 //	volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
-//	id->type = "vfat";
+	IF_FEATURE_BLKID_TYPE(id->type = "vfat";)
 
 	return 0;
 }