smb-lib: fix Type-C removal detection with OTG

When VCONN is enabled while OTG is disabled the CC line which is not
configured for VCONN can be internally pulled down. If the Type-C plug
were removed then Type-C detection would still see that Rd is applied and
not detect the removal.

Fix this by ensuring that OTG is enabled while VCONN is enabled. If OTG
were disabled due to an over-current event then VCONN must also be
disabled.

Implement a retry mechanism if over-current is detected on either VCONN or
VBUS.

Change-Id: Iccfb923bce8f06c7c1270943211ce134ea9ef616
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>