staging: r8188eu: make rtw_init_recv_timer() static

The function rtw_init_recv_timer() is only used in rtw_sta_mgt.c.
Make it static and remove the now empty file os_dep/recv_linux.c.

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/20220807181538.8499-6-straube.linux@gmail.com


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