USB: dwc3-msm: Fix USB connection issue after DCP charger disconnection

Commit "6e3630b5: usb: dwc3-msm: Support
external charging detection " has added check not to start charger
detection in case charger detection is done by external circuit. when otg
driver calls charger_detection API to set charger type to invalid as part
of VBUS disconnect handling, this check prevents to do that. This results
next charger detection not happening after DCP charger disconnection.
Hence fix the issue by moving down the check in the charger_detection API.

Change-Id: I5c614a208f22e4cd9f334c80dae6831bcff64ada
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>