rtl8xxxu: Fix rtl8192eu driver reload issue

The 8192eu suffered from two issues when reloading the driver.

The same problems as with the 8723bu where REG_RX_WAIT_CCA bits 22 and
23 didn't get set in rtl8192e_enable_rf().

In addition it also seems prone to issues when setting REG_RF_CTRL to
0 intead of just disabling the RF_ENABLE bit. Similar to what was
causing issues with the 8188eu.

With this patch I can successfully reload the driver and reassociate
to an APi with an 8192eu dongle.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>