Fix unused variables/parameters in parquet/writer_impl.cu

[davidwendt]

Description

Fix some unused variables/parameters warnings introduced by #13076.
My old nvcc 11.5 compiler found these. Removing some of these found functions that could be removed as well.
Some variables/parameters are now declared with [[maybe_unused]]

/cudf/cpp/src/io/parquet/writer_impl.cu(575): error #177-D: variable "data_col_type" was declared but never referenced

/cudf/cpp/src/io/parquet/writer_impl.cu(906): error #177-D: parameter "stream" was declared but never referenced

/cudf/cpp/src/io/parquet/writer_impl.cu(908): error #177-D: variable "col" was declared but never referenced

/cudf/cpp/src/io/parquet/writer_impl.cu(1290): error #177-D: parameter "max_page_uncomp_data_size" was declared but never referenced

/cudf/cpp/src/io/parquet/writer_impl.cu(1411): error #177-D: parameter "input" was declared but never referenced

/cudf/cpp/src/io/parquet/writer_impl.cu(1712): error #177-D: variable "dict_info_owner" was declared but never referenced

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[davidwendt]

/merge