Remove BoringSSL exception in CFI blacklist.

This got fixed by recent work to be pickier around function
pointers.

Bug: 719699
Change-Id: I684c0ee1d9866ef5517fe983f6e86ab44fb16689
Reviewed-on: https://chromium-review.googlesource.com/c/1282202Reviewed-by: Evgeniy Stepanov <eugenis@chromium.org>
Reviewed-by: Peter Collingbourne <pcc@chromium.org>
Commit-Queue: David Benjamin <davidben@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601402}

tools/cfi/blacklist.txt

@@ -200,10 +200,6 @@ src:*third_party/blink/renderer/platform/wtf/*
 # v8/src/intl.cc
 fun:*LocaleConvertCase*
 
-# Casts away const qualifier
-# third_party/boringssl/src/crypto/pem/pem_lib.c
-fun:*PEM_ASN1_write*
-
 # PropertyCallbackArguments::Call methods cast function pointers
 src:*v8/src/api-arguments-inl.h