[MLIR][XeGPU] XeVM lowering support for load_matrix/store_matrix (#162780)

This PR adds lowering of xegpu.load_matrix/store_matrix to
xevm.blockload/blockstore or and llvm.load/store, depending on wi level
attributes.
It includes a few components: 
   1. adds wi-level attributes: subgroup_block_io.   
2. expand load_matrix/store_matrix op definition to support scalar data
(besides vector data).
2. adds a member function to mem_desc to compute the linearized address
for a nd offsets.
   3. add lowering depending on wi-level attributes: 
a) if subgroup_block_io attribute presents, lower to
xevm.blockload/blockstore
c) else lower to llvm.load/store. If result is a vector, lower to
llvm.load/store with vector operand.

0 files changed, 0 insertions, 0 deletions