Replace all occurences of sprintf with snprintf

THis reduces risks of bufer overflows.

Change-Id: I77f80e76efec16ac0a0af83d76430a8126a7602d
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/4279
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
18 files changed