i965/fs: Default all constants to a location of -1

Otherwise constants which aren't live get an undefined constant location.
When we go to set up param and pull_param we end up assigning all unused
uniforms to slot 0.  This cases the Vulkan driver to segfault because it
doesn't have pull_param.

This fixes bugs in the Vulkan driver introduced in c3fab3d000.

Reviewed-by: Mark Janes <mark.a.janes@intel.com>
1 file changed