usb: pd: Observe PSHardResetTimer for source hard reset

Ensure the PSHardResetTimer is observed in the source case
when receiving a hard reset. Currently it is handled only
when sending a hard reset. This is achieved by moving
PE_SRC_TRANSITION_TO_DEFAULT from usbpd_set_state to usbpd_sm.

Change-Id: Iea0a8cd64fcce14a99b828cadb0f07664ce858f0
Signed-off-by: Jack Pham <jackp@codeaurora.org>