[mlir][tosa] Always generated pad_const and remove input_zp attr for PadOp

Co-authored-by: Udaya Ranga <[email protected]>
Co-authored-by: Tai Ly <[email protected]>

Signed-off-by: Jerry Ge <[email protected]>
Change-Id: I2b7a0169b7ec1158d28779713ad125c061e04592

Author: Jerry-Ge

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

@@ -168,6 +168,10 @@ namespace tosa {
 std::optional<Value> createZeroPointTensor(OpBuilder &builder, Location loc,
                                            Type srcElemType, int64_t zp = 0);
 
+// Create a pad-const const tensor with value of `val` of required data-type
+std::optional<Value> createPadConstTensor(OpBuilder &builder, Location loc,
+                                          Value src, int32_t val = 0);
+
 } // namespace tosa
 } // namespace mlir