cbfstool: Fix build errors when building with clang

Now that we can set CC to an arbitrary compiler, fix issues that clang
finds. Luckily, there were only two trivial errors.

Change-Id: I0fd1f0f263a8ab7004f39cd36ed42d1a1cba5c04
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/5081
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2 files changed