[mlir][tosa] Update Matmul description to align with spec (llvm#130835)

Align description with the spec.
https://www.mlplatform.org/tosa/tosa_spec.html#_matmul

Signed-off-by: Luke Hutton <luke.hutton@arm.com>
Co-authored-by: Luke Hutton <luke.hutton@arm.com>

Author: Jerry-Ge

mlir/include/mlir/Dialect/Tosa/IR/TosaOps.td

@@ -300,12 +300,10 @@ def Tosa_FFT2dOp : Tosa_InferShapedTypeOp<"fft2d", [
 // Operator: matmul
 //===----------------------------------------------------------------------===//
 def Tosa_MatMulOp : Tosa_InferShapedTypeOp<"matmul"> {
-  let summary = "Matrix multiplication with bias";
+  let summary = "Matrix multiplication";
 
   let description = [{
-    Performs a two dimensional matrix multiplication. This allows both inputs to
-    be activations, rather than reserving weights as an attribute in the
-    FULLY_CONNECTED operator.
+    Performs two dimensional matrix multiplications.
   }];
 
   let arguments = (ins