mender: fix ioctl build failure on powerpc64le / power8

Build fails due to missing // +build ppc64le in ioctl_64_bit.go

Add patch to append ppc64le to // +build list.

Fixes
http://autobuild.buildroot.net/results/f22/f222b4389f9308363c386da25ec22a0919bc29fb//



Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>