tools: mkimage: Fixed build warnings

uninitialized retval variable warning fixed
crc32 APIs moved to crc.h (newly added) and build warnings fixed

Signed-off-by: Prafulla Wadaskar <prafulla@marvell.com>
Signed-off-by: Wolfgang Denk <wd@denx.de>

include/u-boot/crc.h

@@ -0,0 +1,33 @@
+/*
+ * (C) Copyright 2009
+ * Marvell Semiconductor <www.marvell.com>
+ * Written-by: Prafulla Wadaskar <prafulla@marvell.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#ifndef _UBOOT_CRC_H
+#define _UBOOT_CRC_H
+
+/* lib_generic/crc32.c */
+uint32_t crc32 (uint32_t, const unsigned char *, uint);
+uint32_t crc32_wd (uint32_t, const unsigned char *, uint, uint);
+uint32_t crc32_no_comp (uint32_t, const unsigned char *, uint);
+
+#endif /* _UBOOT_CRC_H */