staging: r8188eu: merge rtw_{os,}_indicate_scan_done()

staging: r8188eu: merge rtw_{os,}_indicate_scan_done()

Merge rtw_os_indicate_scan_done() into rtw_indicate_scan_done().
It looks like the driver was originaly written to support different
operating systems. We do not need this wrapping into an extra _os_
function obviously.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220819125428.8412-11-straube.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>