usb/langwell_udc: use pm_runtime_get/put instead of sync functions in atmoic context

usb/langwell_udc: use pm_runtime_get/put instead of sync functions in atmoic context

BZ: 14275

As we can not put runtime_suspend/runtime_resume into atmoic context, so it
should not be safe to invoke pm_runtime_get/put_sync in atmoic context

Change-Id: I06ebe6c0635e15c16ea765b7b14c538dda91575c
Signed-off-by: Wu, Hao <hao.wu@intel.com>
Reviewed-on: http://android.intel.com:8080/23995
Reviewed-by: buildbot <buildbot@intel.com>
Reviewed-by: Gross, Mark <mark.gross@intel.com>
Tested-by: Gross, Mark <mark.gross@intel.com>