UPSTREAM: mainboards,ec: provide common declaration for mainboard_ec_init()

Add a header file to provide common declarations that the
mainboards can use regarding EC init.

BUG=chrome-os-partner:56677
BRANCH=None
TEST=None

Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/16734
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: build bot (Jenkins)

Change-Id: Iaa0b37eff4de644e969a18364713b90b7f27fa1c
Reviewed-on: https://chromium-review.googlesource.com/390399
Commit-Ready: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/ec/ec.h

@@ -0,0 +1,24 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef EC_EC_H
+#define EC_EC_H
+
+#ifndef __ACPI__
+/* Entry point doing any mainboard specific EC initialization. */
+void mainboard_ec_init(void);
+#endif
+
+#endif