staging: r8188eu: remove rf_type from issue_assocreq()

rf_type is always RF_1T1R. Remove it from issue_assocreq() and remove
related dead code.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211128170924.5874-3-straube.linux@gmail.com


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