i965/drm: Use list_for_each_entry_safe in a couple of cases.
i965/drm: Use list_for_each_entry_safe in a couple of cases.

Suggested by Chris Wilson.  A tiny bit simpler.

Reviewed-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler