staging: rtl8723au: phy_SsPwrSwitch92CU() was never called with bRegSSPwrLvl != 1

Get rid of the alternate code paths since these weren't used and have
never been tested according to the in-code comments.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>