staging: rtl8192e: Rename r8192_wx_set_rts

Use naming schema found in other rtlwifi devices.
Rename r8192_wx_set_rts to _rtl92e_wx_set_rts.

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>