staging: r8188eu: remove channel parameters from rtw_sitesurvey_cmd

The rtw_sitesurvey_cmd function may receive an array of channels in the
ch and ch_num parameters. All of the callers set ch = NULL and ch_num = 0.

Remove the two parameters from rtw_sitesurvey_cmd and the code to process
them.

Tested-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220905195612.81945-1-martin@kaiser.cx


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