misc: Make sure byteorder.h does not get loaded more than once

It's an important header, used in many place and it's thus very easy to
get different sub-system loading it thus leading to redefinition error.
(net_buf and net drivers for instance).

Change-Id: Icbbbc2fc0abcb007d8950dd06b601717960e7215
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>