v4l: xilinx-multi-scaler: Fix stop streaming

v4l: xilinx-multi-scaler: Fix stop streaming

Driver is setting bit on stop streaming which is incorrect
This patch corrects the functionality by clearing the bit
on stop streaming.

Signed-off-by: Suresh Gupta <suresh.gupta@xilinx.com>
Reviewed-by: Hyun Kwon <hyun.kwon@xilinx.com>
Reviewed-by: Satish Kumar Nagireddy <satish.nagireddy.nagireddy@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>