USB: dwc3: msm: add charger detection for floated D+ and D-

Floated charger means "D+/D- floated charger". According batt
charging spec 1.2, during primary detection, the DP voltage
is VDP_SRC, DM voltage may not exceed VDAT_REF, it's same to
standard downstream port(SDP). Introducing data contact
detection(DCD) here to distinguish between SDP and floated
charger. If DCD detected, it's SDP, otherwise floated charger
is detected. Also rename UNSUPPORTED charger as FLOATED charger
as data lines D+/D- are floating.

Change-Id: I0fd307c512f46331e6e1d80759c1585fc1db8a39
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>