staging: r8188eu: remove ODM_SingleDualAntennaDefaultSetting()

Function ODM_SingleDualAntennaDefaultSetting() is not used,
remove it.

Acked-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211015163507.9091-3-straube.linux@gmail.com


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