util: Fix SCons build.

Fixes: 848e7b94 ("util: Move stack debug functions to src/util")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Part-of: <mesa/mesa!6199>
72 jobs for !6199 with fix-scons-build in 25 minutes and 13 seconds (queued for 4 seconds)
merge request