Enable coverage for libmediandk

The linker error previously seen no longer happens - it probably got
fixed by a non-toolchain-related change since clang-r349610 from Feb
2019 is able to build libmediandk with coverage in the Q branch.

Bug: http://b/124522995
Test: mmma NATIVE_COVERAGE=true frameworks/av/media/ndk and check that
built libmediandk.so has __gcov_flush symbol
Test: Presubmit target cf_x86_phone-userdebug_coverage

Change-Id: I24f0c3fbbea733a521ea97e4fe28c94c6f607119
(cherry picked from commit fec6b9d677ca5fef3413ef10fbb0178e76b37218)

media/ndk/Android.bp

diff --git a/media/ndk/Android.bp b/media/ndk/Android.bp
index a3cabd8..9c7a630 100644
--- a/media/ndk/Android.bp
+++ b/media/ndk/Android.bp
@@ -110,10 +110,6 @@
         symbol_file: "libmediandk.map.txt",
         versions: ["29"],
     },
-
-    // Bug: http://b/124522995 libmediandk has linker errors when built with
-    // coverage
-    native_coverage: false,
 }
 
 llndk_library {