uwb: Remove umc bus legacy suspend/resume support

There are currently no umc drivers implementing suspend/resume, so remove
the legacy suspend/resume support from the framework. If a umc driver ever
wants to implement suspend/resume they can use dev_pm_ops, which works out
of the box without any additional support necessary from the bus itself.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>