Move load_firmware() to separate file

The idea is to share loading code between bootloaders and rolo().

Change-Id: I1656ed91946d7a05cb7c9fa7a16793c3c862a5cd
Reviewed-on: http://gerrit.rockbox.org/190
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>

firmware/include/loader_strerror.h

@@ -0,0 +1,38 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ *
+ * Copyright (C) 2013 Marcin Bukat
+ *
+ * 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; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+enum error_t {
+    EFILE_EMPTY = 0,
+    EFILE_NOT_FOUND = -1,
+    EREAD_CHKSUM_FAILED = -2,
+    EREAD_MODEL_FAILED = -3,
+    EREAD_IMAGE_FAILED = -4,
+    EBAD_CHKSUM = -5,
+    EFILE_TOO_BIG = -6,
+    EINVALID_FORMAT = -7,
+    EKEY_NOT_FOUND = -8,
+    EDECRYPT_FAILED = -9,
+    EREAD_HEADER_FAILED = -10,
+    EBAD_HEADER_CHKSUM = -11,
+    EINVALID_LOAD_ADDR = -12,
+    EBAD_MODEL = -13
+};
+
+char *loader_strerror(enum error_t error);