Drop all the infrastructure for taddr properties (ie ones which
are 'hwaddr' sized). These are now unused, and any further desired
use would be rather questionable since device properties shouldn't
generally depend on a type that is conceptually variable based on
the target CPU. 32 or 64 bit integer properties should be used instead
as appropriate for the specific device.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>