Update comments for IBiometricsFingerprint@2.3

This CL adds a comment that discourages use of this interface. The AIDL
interface, IFingerprint, should be used instead.

Bug: 160189286
Test: hidl-gen -L check android.hardware.biometrics.fingerprint@2.3::IBiometricsFingerprint
Change-Id: Ifafb191ac16e03e60d677fce6dc9e41e87bad0c0
diff --git a/biometrics/fingerprint/2.3/IBiometricsFingerprint.hal b/biometrics/fingerprint/2.3/IBiometricsFingerprint.hal
index 13f03c5..378b564 100644
--- a/biometrics/fingerprint/2.3/IBiometricsFingerprint.hal
+++ b/biometrics/fingerprint/2.3/IBiometricsFingerprint.hal
@@ -19,6 +19,10 @@
 import @2.2::IBiometricsFingerprint;
 
 /**
+ * New use of this interface is strongly discouraged. The recommended option is
+ * to use the AIDL interface, android.hardware.biometrics.fingerprint
+ * (IFingerprint).
+ *
  * The interface for biometric fingerprint authentication.
  */
 interface IBiometricsFingerprint extends @2.2::IBiometricsFingerprint {