Populate `max_load_instruction_bits`, `simds_per_wgp`, `vgpr_space_bits` on all GPUs

[bjacob]

In https://github.com/iree-org/iree/pull/18839 we are introducing 3 new fields to TargetGpuAttr: max_load_instruction_bits, simds_per_wgp, vgpr_space_bits on all GPUs.

For now they only are populated for CDNA3. They should be populated for other GPUs, as a step towards supporting data tiling on arbitrary GPUs.