hexagon: MUL_MAT and MUL_MAT_ID fusion and fixes (#28202)
* hex-mm: fuse QKV and FFN matmuls that land on HMX
* hex-mm: remove hardcoded ne[1] < 32K restriction
* hex-get-rows: explicitly reject repacked Q8_0 just in case somebody decided to add an override
* hex-mm: correct overhead sizing to make sure we dont exceed vtcm budget for large dims
* hex-mm: fuse MUL_MAT_ID into MUL_MAT_ID_NX (2x,3x,...) where possible
* hex-fusion: update opbatch and opqueue sizing to acount for new fusion and reduce overhead for trace buffer alloc
* hex-bufs: sort buffers while finalizing opbatch, helps avoid va space fragmentation
* hex-bufs: add simple va defrag to make sure we dont abort just because the va space is fragmented
* hex-mm: replaced more scalar divs with fastdiv and minor cleanup
* hex-mm: tighten up supported fusion checks to exactly match supported kernels
