smb-lib: add support for float charger reporting

Report adapter type as USB_FLOAT if charger hardware detects a
floating charger this will allow USB driver to try/start
communication over Tx/Rx line during compliance testing.

Change-Id: I1d1e91e99806423a3e995876e9db4582ed0f1b08
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>