Minor build fixes.

I made these two tiny changes to SeaBIOS when I was playing with the
HEAD version.

The Makefile change prevents the test command from failing if CC
contains a space.

The coreboot change prevents a warning on our gcc 4.5.2 in certain
circumstances when sizeof seems to be unsigned long int instead of
unsigned int.

They're both unintrusive, shouldn't have potential for breaking
anything.

Signed-off-by: Stefan Reinauer <stepan@coreboot.org>