Add current.txt HAL sections for S.

Adding these now, with a note that AIDL interfaces should be preserved,
to avoid some merge conflicts.

Bug: 147496715
Test: N/A
Change-Id: I67f6c5d583b853516c7203edb77f3c5fa841863b
diff --git a/current.txt b/current.txt
index 38e1c66..0caec17 100644
--- a/current.txt
+++ b/current.txt
@@ -762,3 +762,8 @@
 2ce1f7fb52e49f80b13a9b153d491bce530552f02357ea729acae922a8659f93 android.hardware.wifi.supplicant@1.3::ISupplicantStaIfaceCallback
 77531c8d048f8f8ae532babd0ca86332a865ec9aace1b051226ef2b21123e645 android.hardware.wifi.supplicant@1.3::ISupplicantStaNetwork
 98592d193a717066facf91428426e5abe211e3bd718bc372e29fb944ddbe6e7c android.hardware.wifi.supplicant@1.3::types
+
+# ABI preserving changes to HALs during Android S
+
+# HALs released in Android S
+# NOTE: new HALs are recommended to be in AIDL