hexagon: rope updates

[tboinovski1]

Overview

MROPE/IMROPE/VISION updates.

Additional information

• MROPE/IMROPE theta-pick vectorization
• NEOX rotate + aligned tail copy tightening and theta cache vectorization on v75
• In-place RoPE for all scenarios and removal of ctx->spad/legacy timers.
• Kernel params + host-side VTCM requirement enforcement, mode-check tightening/param cleanup

  ┌────────┬────────────────────────────────┬────────────┬────────────┬─────────────────────┐
  │  Mode  │             Shape              │   Before   │   After    │       Speedup       │
  ├────────┼────────────────────────────────┼────────────┼────────────┼─────────────────────┤
  │ MROPE  │ [128,12,512,1]                 │ 586–596 us │ 100–102 us │ ~5.6–5.9×           │
  ├────────┼────────────────────────────────┼────────────┼────────────┼─────────────────────┤
  │ IMROPE │ [128,12,512,1]                 │ 615–639 us │ 99–101 us  │ ~6.1–6.4×           │
  ├────────┼────────────────────────────────┼────────────┼────────────┼─────────────────────┤
  │ VISION │ [80,16,2,1]                    │ 8.5–8.6 us │ 5.6–5.7 us │ ~1.5-1.7×               │
  ├────────┼────────────────────────────────┼────────────┼────────────┼─────────────────────┤
  │ NEOX   │ [64,8,512,1], [80,32,512,1]    │ 54–242 us  │ 52–230 us  │ ~1.05–1.11×         │
  ├────────┼────────────────────────────────┼────────────┼────────────┼─────────────────────┤
  │ NORMAL │ [128,32,512,1], [128,64,512,1] │ 259–517 us │ 259–536 us │ ~0.98–1.06× │
  └────────┴────────────────────────────────┴────────────┴────────────┴─────────────────────┘

Testing: 288/288 tests passed (all f32 tests still passing)

Requirements

• I have read and agree with the contributing guidelines
• AI usage disclosure: Yes to reason about and test the code refactoring.

[max-krasnyansky]

@lhez for review & second ack