usb: dwc3-msm: Clear the err_evt_seen flag on cable disconnect

During cable disconnect, driver cancels the block reset work
which was queued due to erratic event. If the work is not running,
err_evt_seen flag will remain set. This results in USB enumeration
failure, since legitimate interrupts will be ignored. Hence clear
the flag after cancelling the work. Also remove the cancelling of
block reset work from suspend routine, since it is already handled
in dwc3_msm_power_set_property_usb().

CRs-fixed: 750129
Change-Id: I76bb0fa5e6be6b39307a2b82414054a3fdbe3378
Signed-off-by: Azhar Shaikh <azhars@codeaurora.org>