Add device_opened flag to indicate device node open success. Use device_opened flag to allow execution of IOCTL and device teardown functionality. Jira THWPM-41 Change-Id: I218a45abed1de9f314cba696fd86c9bd8596cacc Signed-off-by: Vedashree Vidwans <vvidwans@nvidia.com> Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2675514 Reviewed-by: svcacv <svcacv@nvidia.com> Reviewed-by: svc_kernel_abi <svc_kernel_abi@nvidia.com> Reviewed-by: Seema Khowala <seemaj@nvidia.com> Reviewed-by: Vasuki Shankar <vasukis@nvidia.com> GVS: Gerrit_Virtual_Submit