- gem_lmem: Replace bump allocator with best-fit free-list (BTreeMap) that
tracks individual allocations and coalesces freed blocks on both sides
- mocs: Add init_pat() - programs PAT index 0-7 with WB/WC/WT/UC for Gen9+,
and WB-only for Gen12+; called after init_mocs() in IntelDriver init
- regs_gt: Add PAT register constants (GEN8_PRIVATE_PAT_*, GEN12_PAT_INDEX,
GEN8_PPAT_* cache attributes) and TBIMR_FAST_CLIP
- PAT programming: Gen9 uses 0x40E0 base with LLC/LLCELLC attributes,
Gen12 uses 0x4800 base with simple WB/WC/WT/UC (no LLC on Xe2)
- All changes compile clean (0 errors)
vasilito
31c19fe839