[NVPTX] Add tcgen05 alloc/dealloc intrinsics (#124961)
This patch adds intrinsics for the tcgen05 alloc/dealloc
family of PTX instructions. This patch also adds an
addrspace 6 for tensor memory which is used by
these intrinsics.
lit tests are added and verified with a ptxas-12.8 executable.
Documentation for these additions is also added in NVPTXUsage.rst.
Signed-off-by: Durgadoss R <durgadossr@nvidia.com>
