hexagon: new vtcm layouts and improved pipelines for MUL_MAT, MUL_MAT_ID and FLASH_ATTN_EXT (#25425)

• hex-fa: refactor kernel param compute to use common layout builder

• hmx: add explicit compiler barriers to make hmx funcs more robust

• hex-vtcm: more generic vtcm layout builder for mm and flash-attn kernels

• hex-hmx: unroll inner kernels

• hex-hmx: use inline asm instead of intrinsics to avoid compiler issues

• hex-hmx: define inline asm macros and simplify code

• hex-hmx: replace leftover intrinsics

• hmx-fa: minor cleanup for hmx asm

• hmx-mm: move per-task stucts out of the kernels header

• hmx-mm: simplify core_dot_chunk

• hmx-mm: simplify inner loops that call hmx instructions

• hmx-mm: proper instrumentation for activation prep work for dma pipelined version

• hmx-mm: update a-prep loop for better prefetch

• hex-vtcm: improved vtcm layout alloc for mm to support overlapping areas

• hmx-mm: reduce the number of act fetch tows to 4 for now, going larger doesnt help here

• hex-hmx: always use hmx-queue in all modes

• hmx-mm: update comments and minor formatting

• hmx-mm: further improve synchro fallback path to prefetch the weights earlier

• hex-fa: further pipeline improvements (earlier prefetch)

• hmx-mm: cleanup dma pipelines to use dst cached in the queue

• hmx-fa: minor cleanup and opts for fa dma pipelines

• hmx-fa: optimize q-prep stage with dma and unrolling

• hmx-fa: use o_tile size from layout instead of computing it

• hmx-mm: cleanup types and size handling

• hmx-mm: replace divs with fastdiv in qprep loops

• hmx-fa: minor update/formatting to q_tile handling

• hmx-fa: cleanup the layout to avoid overpadding

• hmx-fa: simplified and improved cost mode for hmx fa solver that uses vtcm layout funcs

• hmx-queue: add support queue wakeup and make suspend async to avoid hmx-lock latency

• hex-hmx: move queue wakeup / suspend to the op-batch level

• hex-threads: add hybrid polling to workpool

• hex-mm: fix trailing spaces