Remove old workaround for old version of boringssl.

See
https://fuchsia-review.git.corp.google.com/c/third_party/tink/+/255788

Change-Id: Ie797e4e52ccf107b6650a7a5bdb13d3d2dc2c334
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/tink/+/769307
Fuchsia-Auto-Submit: Alexandre Zani <azani@google.com>
Commit-Queue: Auto-Submit <auto-submit@fuchsia-infra.iam.gserviceaccount.com>
Reviewed-by: Zach Bush <zmbush@google.com>
diff --git a/cc/subtle/xchacha20_poly1305_boringssl.cc b/cc/subtle/xchacha20_poly1305_boringssl.cc
index 6376782..3a2fb6a 100644
--- a/cc/subtle/xchacha20_poly1305_boringssl.cc
+++ b/cc/subtle/xchacha20_poly1305_boringssl.cc
@@ -32,11 +32,6 @@
 namespace tink {
 namespace subtle {
 
-// TODO(azani): Remove after we upgrade BoringSSL.
-EVP_AEAD* EVP_aead_xchacha20_poly1305() {
-  return nullptr;
-}
-
 static const bool IsValidKeySize(uint32_t size_in_bytes) {
   return size_in_bytes == 32;
 }