media: nxp: imx8-isi: m2m: Delay power up until streamon

media: nxp: imx8-isi: m2m: Delay power up until streamon

There's no need to power up the device when userspace opens it. Delay
the operation until streamon.

Link: https://lore.kernel.org/r/20250821135123.29462-2-laurent.pinchart@ideasonboard.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Guoniu Zhou <guoniu.zhou@nxp.com>
Tested-by: Guoniu Zhou <guoniu.zhou@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>