stress-ng: fix build with kernel headers v3.9
Add a patch correcting the kernel headers version test macro.
Fixes:
http://autobuild.buildroot.net/results/cbf/
cbfb80117840bddd5712bcda3caeaaff61745b0b/
http://autobuild.buildroot.net/results/649/
64941ac5b7dcd9c100bdc47cdfe73cce5f23c3d8/
http://autobuild.buildroot.net/results/741/
741f5881d3cb745d1003ede3f762c20eb72de0b5/
Cc: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>