power: smblib: make OTG_VOTER suspend input only in OTG state

USB input is suspended in OTG mode. In current implementation,
OTG_VOTER votes to suspend input when the typec enters DFP
mode, which, however, may just be in DRP mode without sink
device attached.

Fix it by voting to suspend input only in DFP mode with USB
present.

CRs-Fixed: 2091095
Change-Id: I4c18a91af8161a6b681dc29489736167f2dd9d5c
Signed-off-by: Harry Yang <harryy@codeaurora.org>