Fix fuzzer signatures.

They take a const pointer. See
http://llvm.org/docs/LibFuzzer.html#building

BUG=chromium:655016

Change-Id: Id6c7584c7a875e822b1fbff72163c888d02a9f44
Reviewed-on: https://boringssl-review.googlesource.com/11580
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: Steven Valdez <svaldez@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/fuzz/spki.cc b/fuzz/spki.cc
index 939d719..b54e4b8 100644
--- a/fuzz/spki.cc
+++ b/fuzz/spki.cc
@@ -16,7 +16,7 @@
 #include <openssl/evp.h>
 #include <openssl/mem.h>
 
-extern "C" int LLVMFuzzerTestOneInput(uint8_t *buf, size_t len) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *buf, size_t len) {
   CBS cbs;
   CBS_init(&cbs, buf, len);
   EVP_PKEY *pkey = EVP_parse_public_key(&cbs);