[mlir][memref][spirv] Add SPIR-V Image Lowering (#150978)

Adds an initial conversion in the Memref -> SPIR-V lowering for images.
Any memref in the "Image" storage-class/address-space will be considered
for lowering to the `!spirv.image` type during Memref to SPIR-V
conversion. Initially only the reading of sampled images are support and
images are read via the `OpImageFetch` instruction. Future work should
expand the conversion patterns to target non-sampled images and add
support for image write operations.

Images are supported for fp32, fp16, int32, uint32, int16 and uint16
types and lit tests have been added to verify this is the case along
with negative testing to check the cases where images aren't supported.

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Signed-off-by: Jack Frankland <jack.frankland@arm.com>

0 files changed, 0 insertions, 0 deletions