cuda: fix RDNA3.5 MMQ codegen regression after profiling cleanup

Add MMQ_HIP_TILE_BARRIER() tile-scope __syncthreads() at K-loop phase
boundaries on HIP+RDNA3.5 to restore pp128 throughput after removing dead
threadIdx.z cold/hot loop split.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: liangliangchang