cbfstool: Fill memory allocated in create_cbfs_file() with 0xff

This should improve programming speed a bit.

Signed-off-by: Peter Stuge <peter@stuge.se>

Index: util/cbfstool/common.c
===================================================================
--- util/cbfstool/common.c	(revision 4973)
+++ util/cbfstool/common.c	(working copy)
@@ -279,6 +279,7 @@
 		       headersize);
 		exit(1);
 	}
+	memset(newdata, 0xff, *datasize + headersize);
 	struct cbfs_file *nextfile = (struct cbfs_file *)newdata;
 	strncpy(nextfile->magic, "LARCHIVE", 8);
 	nextfile->len = htonl(*datasize);