usb: misc: ks_bridge: Don't enable runtime suspend by default

Not all devices support selective suspend and fail to respond
in dload mode when suspended. Hence don't enable it by default
from driver. User can later enable it using sysfs if needed.

Change-Id: Ifff5891d772011f812e8ae3356bf847dced78bfb
CRs-fixed: 2009286
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>