Add some missing includes

When building BCM sources individually, this gets missed.

Change-Id: I58858da441daaeffc5e54b653f5436fe817c4178
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/59306
Auto-Submit: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>

crypto/fipsmodule/self_check/self_check.c

@@ -26,6 +26,7 @@
 #include <openssl/ec.h>
 #include <openssl/ecdsa.h>
 #include <openssl/ec_key.h>
+#include <openssl/hkdf.h>
 #include <openssl/hmac.h>
 #include <openssl/nid.h>
 #include <openssl/rsa.h>

crypto/fipsmodule/tls/kdf.c

@@ -54,6 +54,7 @@
 
 #include <openssl/bytestring.h>
 #include <openssl/digest.h>
+#include <openssl/hkdf.h>
 #include <openssl/hmac.h>
 #include <openssl/mem.h>