staging: rtl8723au: Reduce number of duplicate defines for link state

We use the MSR bits to define link state anyway, so no point having an
additional two sets of defines for the same thing.

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