CVE-2026-74454 drm/vc4: Supply the overflow slot size in BPOS, not the whole bin BO size

In the Linux kernel, the following vulnerability has been resolved: drm/vc4: Supply the overflow slot size in BPOS, not the whole bin BO size vc4overflowmemwork points BPOA at a 512KB slot inside the 16MB binner BO, but writes the size of the whole BO to BPOS. On every binner out-of-memory event...