When no valid MRC cache area is found, the mrc_cache data structure was used without prior initialization. This sometimes caused a long delay when booting because compute_ip_checksum would checksum up to 4GB of memory. Change-Id: I6a0ca1aa618838bbc3d042be425700fc34b427f2 Signed-off-by: Stefan Reinauer <reinauer@google.com> Reviewed-on: http://review.coreboot.org/1277 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>