cbfstool: Change "locate" output to prefix "0x".

Currently "cbfstool locate" outputs a hex number without "0x" prefix.
This makes extra step (prefix 0x, and then generate another temp file) in build
process, and may be a problem when we want to allow changing its output format
(ex, using decimal). Adding the "0x" in cbfstool itself should be better.

Change-Id: I639bb8f192a756883c9c4b2d11af6bc166c7811d
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: http://review.coreboot.org/2201
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>

util/cbfstool/cbfstool.c

@@ -412,7 +412,7 @@ static int cbfs_locate(void)
 	location = cbfs_find_location(param.cbfs_name, filesize,
 					param.name, param.alignment);
 
-	printf("%x\n", location);
+	printf("0x%x\n", location);
 	return location == 0 ? 1 : 0;
 }