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>
diff --git a/include/common.h b/include/common.h
index 35f12c0..f7c93bf 100644
--- a/include/common.h
+++ b/include/common.h
@@ -624,9 +624,7 @@
 char *	strmhz(char *buf, long hz);
 
 /* 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);
+#include <u-boot/crc.h>
 
 /* common/console.c */
 int	console_init_f(void);	/* Before relocation; uses the serial  stuff	*/