Explicitly add lld's relr relocation flags for Android Pie and above

Bug: http://b/119086751

https://android-review.googlesource.com/c/837025 disabled lld relocation
packing globally and enabled it for soong modules targeting pie and
above.  Turn it on for Android.mk modules as well.

Test: grep for -Wl,pack-dyn-relocs=android in
      out/build-aosp_<device>.ninja

Change-Id: I81b8625073aa6b364219b8cf3122b69c95ec7589