intelmetool: Include <sys/io.h> for musl-libc

This allows compiling the program using musl-libc, since otherwise
iopl(2) is undeclared.

Change-Id: Ia27203cf47b9be3f7bf1ad422c8f490caeae8f56
Signed-off-by: Ivan J. <parazyd@dyne.org>
Reviewed-on: https://review.coreboot.org/23834
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

util/intelmetool/intelmetool.c

@@ -18,6 +18,7 @@
 #include <unistd.h>
 #include <string.h>
 #include <cpuid.h>
+#include <sys/io.h>
 
 #ifdef __NetBSD__
 #include <machine/sysarch.h>