[mlir][nvgpu] Delete nvgpu dialect unused variable kMaxTMALastdimByte (NFC) (#155825)

Since the size of the last dimension of TMA is no longer fixed at 128
bytes, remove the kMaxTMALastdimByte.

Author: linuxlonelyeagle

mlir/include/mlir/Dialect/NVGPU/IR/NVGPUDialect.h

@@ -46,8 +46,8 @@ constexpr unsigned kMaxTMATensorDimension = 5;
 /// to be traversed along each of the kMaxTMATensorDimension (tensorRank)
 /// dimensions, must be non-zero and less than or equal to 256.
 constexpr unsigned kMaxTMADimension = 256;
-/// Last dimension of 2D+ TMA must be 128 bytes
-constexpr unsigned kMaxTMALastdimByte = 128;
+/// The bytes in the last dimension of the tensor map must be a multiple of 16.
+constexpr unsigned kTMALastdimByte = 16;
 
 #define GET_ATTRDEF_CLASSES
 #include "mlir/Dialect/NVGPU/IR/NVGPUAttrDefs.h.inc"

mlir/lib/Dialect/NVGPU/IR/NVGPUDialect.cpp

@@ -424,7 +424,7 @@ std::optional<InFlightDiagnostic> verifyTmaDescriptorWithMemref(
 
   int lastDimBytes =
       descMemref.getShape().back() * descMemref.getElementTypeBitWidth() / 8;
-  if (lastDimBytes % 16 != 0) {
+  if (lastDimBytes % kTMALastdimByte != 0) {
     return op->emitError() << "the bytes in the last dimension of the tensor "
                               "map must be a multiple of 16";
   }