lib: Add a drm_open_any_render() that will try to use render nodes

I was fedup with having to run my tests as root and not being able to
use my usual setup for tests that only exercise the GT part of the GPU.

Render nodes to the rescue!

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

lib/drmtest.h

@@ -50,6 +50,7 @@ drm_intel_bo * gem_handle_to_libdrm_bo(drm_intel_bufmgr *bufmgr, int fd,
 
 int drm_get_card(void);
 int drm_open_any(void);
+int drm_open_any_render(void);
 
 void gem_quiescent_gpu(int fd);