kmod: define -UNDEBUG to include asserts

The cyclic dependency checking in depmod currently assert fails when a cycle
is encountered. Define -UNDEBUG to ensure the assert is reported.

Bug: 142892240
Test: run depmod on modules with a cycle
Change-Id: I79d7f3e29a54b4ffd27ac1945b1cb0f8a52d76ed
diff --git a/Android.bp b/Android.bp
index 2ebdd16..f6edaa0 100644
--- a/Android.bp
+++ b/Android.bp
@@ -14,6 +14,7 @@
         "-DHAVE_CONFIG_H",
         "-DANOTHER_BRICK_IN_THE",
         "-DSYSCONFDIR=\"/tmp\"",
+        "-UNDEBUG",
     ],
     target: {
         linux_glibc: {