BUILD: ssl: adjust guard for X509_get_X509_PUBKEY(x)

BoringSSL defines that function since
https://boringssl.googlesource.com/boringssl/+/33f8d33af0dcb083610e978baad5a8b6e1cfee82
diff --git a/include/haproxy/openssl-compat.h b/include/haproxy/openssl-compat.h
index 123b76e..d34a22e 100644
--- a/include/haproxy/openssl-compat.h
+++ b/include/haproxy/openssl-compat.h
@@ -119,7 +119,7 @@
 
 #endif // OpenSSL < 0.9.8
 
-#if (((HA_OPENSSL_VERSION_NUMBER < 0x1000000fL) || defined(OPENSSL_IS_BORINGSSL)) && !defined(X509_get_X509_PUBKEY))
+#if ((HA_OPENSSL_VERSION_NUMBER < 0x1000000fL) && !defined(X509_get_X509_PUBKEY))
 #define X509_get_X509_PUBKEY(x) ((x)->cert_info->key)
 #endif