power: smb5-lib: Add wireless support in DC psy

Parallel wireless charging requires adjustable voltage output from
Wireless receiver, implemented via input_voltage_regulation property
in wireless psy.

In addition, DC psy also supplies other current/voltage access.

Change-Id: I56e2846f18e9827486569d9c2fa988bc77993e8e
Signed-off-by: Harry Yang <harryy@codeaurora.org>