iommufd/fault: Destroy response and mutex in iommufd_fault_destroy()

iommufd/fault: Destroy response and mutex in iommufd_fault_destroy()

Both were missing in the initial patch.

Fixes: 07838f7fd529 ("iommufd: Add iommufd fault object")
Link: https://patch.msgid.link/r/bc8bb13e215af27e62ee51bdba3648dd4ed2dce3.1736923732.git.nicolinc@nvidia.com
Cc: stable@vger.kernel.org
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>