usb: pd: start USB host mode with DR_SWAP when current_dr is UFP

Commit 38e9b250 ("usb: pd: Start USB host mode functionality with
SRC_STARTUP") has removed functionality which was starting USB host
mode after finding DP capable device. This results into no USB host
mode functionality with DR_SWAP request when current_dr is UFP. Fix
this issue by starting USB host mode with super speed on receiving
DR_SWAP request when current_dr is UFP.

CRs-Fixed: 2082369
Change-Id: I47ab6d55f495c6884eb5b6bb18181aa8deaf0ac1
Signed-off-by: Mayank Rana <mrana@codeaurora.org>