rtl8xxxu: Do not use hard-wired RF enable settings for 8723bu

These settings simply block the 8723bu, for now leave an empty
function.

With this change we can finally communicate with aliens using the
8723bu!

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