staging/rtl8192u: Initialize variables in the definition block

Initialize the pre_cmd_cnt, post_cmd_cnt and rf_cmd_cnt variables in the
definition block as it is not necessary to do this in the middle of the
function.

Signed-off-by: Len Baker <len.baker@gmx.com>
Link: https://lore.kernel.org/r/20210824073643.GA7396@titan


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