Fix include path.

This happened to be working only because of lucky -I argument and At the
same time, include digest.h since this file references |EVP_sha1| and
other digest-related functions.

Change-Id: I0095ea8f5ef21f6e63b3dc819932b38178e09693
Reviewed-on: https://boringssl-review.googlesource.com/28244
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/crypto/fipsmodule/tls/kdf.c b/crypto/fipsmodule/tls/kdf.c
index 7c7fcc3..347e998 100644
--- a/crypto/fipsmodule/tls/kdf.c
+++ b/crypto/fipsmodule/tls/kdf.c
@@ -52,11 +52,12 @@
 
 #include <assert.h>
 
+#include <openssl/digest.h>
 #include <openssl/hmac.h>
 #include <openssl/mem.h>
 
 #include "internal.h"
-#include "../crypto/internal.h"
+#include "../../internal.h"
 
 
 // tls1_P_hash computes the TLS P_<hash> function as described in RFC 5246,