buildroot

luvi: fix build with LuaJIT 2.0.5

Luvi got broken by the bump of LuaJIT from 2.0.4 to 2.0.5 due to a
hardcoded path.

Fixes:

 http://autobuild.buildroot.net/results/3eef12dbe07fb375e87b2b2898dcc5ef0c11e7a5/

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>