Disable clang-tidy for upstream files.

Bug: 264302877
Test: presubmit tests; make tidy-bionic_subset
Change-Id: I278201c62e70898103bf20ce8823106418c8fb05
diff --git a/libm/Android.bp b/libm/Android.bp
index 2748871..3e271fa 100644
--- a/libm/Android.bp
+++ b/libm/Android.bp
@@ -29,6 +29,7 @@
 
     whole_static_libs: ["libarm-optimized-routines-math"],
 
+    tidy_disabled_srcs: ["upstream-*/**/*.c"],
     srcs: [
         "upstream-freebsd/lib/msun/bsdsrc/b_tgamma.c",
         "upstream-freebsd/lib/msun/src/catrig.c",