ggml-hexagon: gelu optimization (llama/18151)

ggml-hexagon: gelu optimization (llama/18151)

* feat: working gelu with src0 put on vtcm

* feat: gelu ping-pong for both in and out

* fix: fixu compile error

* break: distinguish dma ddr->vtcm and vtcm->ddr operation

* fix: fix dma queue size

* break: update dma api to either pop src or dst ptr

* fix: fix activation vtcm allocation issue for src1 when swapperd

* refactor: ping-pong gelu logic to avoid unnecessary if else

* dma: improved queue interface and prefetch handling

* gelu: fix N+2 block prefetch

---------

Co-authored-by: Max Krasnyansky <redacted>