power: smb135x-charger: Use UNKNOWN usb type for APSD failure

The driver forces the USB type to SDP when APSD failure happens.
The USB driver uses software based detection if the type is set
to UNKNOWN.

Use UNKNOWN instead of SDP in case of failure.

Change-Id: I03bf62253655c1822240d592d0444cc8c7a4ba06
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>