staging:rtl8192u: Refactor DELBA_PARAM_SET - Style

Remove the typedef directive from union DELBA_PARAM_SET, to clear the
checkpatch issue with CamelCase naming.

Rename the union to lowercase to comply with the coding standard.

These changes are coding style changes which should have no impact on
runtime code execution.

Signed-off-by: John Whitmore <johnfwhitmore@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>