i965: Fix memory leaks in brw_upload_cs_work_groups_surface().
This was taking a reference to the 64kB upload buffer and never returning it, leaking a reference each time this atom triggered.
This leaked lots of 64kB upload BOs, eventually running us out of of VMA space. This would usually happen when using mpv to watch a movie, after 20-40 minutes.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110134
Fixes: 63d7b33f i965/cs: Setup surface binding for gl_NumWorkGroups
Edited by Eric Engestrom