x86, tools: Remove unneeded header files from tools/build.c

x86, tools: Remove unneeded header files from tools/build.c

We include <sys/sysmacros.h> and <asm/boot.h>, but none of those
header files actually provide anything this file needs.  Furthermore,
it breaks cross-compilation, so just remove them.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Bowler <nbowler@elliptictech.com>
Link: http://lkml.kernel.org/r/20120229111322.9eb4b23ff1672e8853ad3b3b@canb.auug.org.au