Intel MPX was recently enabled on x86 (_append_x86) but that didn't
enable it on x86-64. Explicitly enable libmpx on x86-64 too.
(From OE-Core rev: 5111bd5e666408dbca7db0e6d664fe0103744253)
Signed-off-by: Mikko Ylinen <mikko.ylinen@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>