staging: r8188eu: core: remove unused variable sz

Remove the unused variable sz from function dynamic_chk_wk_hdl.
This variable is not used on function.

Signed-off-by: Saurav Girepunje <saurav.girepunje@gmail.com>
Link: https://lore.kernel.org/r/YYNNDXtkICWpk6qj@Sauravs-MacBook-Air.local


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>