Free generated mirror-LUT data structures to avoid memory leak

This is a technicality, but this satisfies the clang dynamic memory
analyzer.

Signed-off-by: Laslo Hunhold <dev@frign.de>
diff --git a/gen/bidirectional.c b/gen/bidirectional.c
index 3dd034e..b4a4fb7 100644
--- a/gen/bidirectional.c
+++ b/gen/bidirectional.c
@@ -499,5 +499,10 @@
 	                                      mm_mirror.minorlen, get_value,
 	                                      comp_mirror.data);
 
+	free(comp_mirror.data);
+	free(comp_mirror.offset);
+	free(mm_mirror.major);
+	free(mm_mirror.minor);
+
 	return 0;
 }