drm/xe/vm: Fix SVM leak on resv obj alloc failure in xe_vm_create()

Summary

In the Linux kernel, the following vulnerability has been resolved: drm/xe/vm: Fix SVM leak on resv obj alloc failure in xe_vm_create() Commit 9e9787414882 ("drm/xe/userptr: replace xe_hmm with gpusvm") made xe_svm_init() unconditional in xe_vm_create() and extended it to also initialize a "simple" gpusvm state for non-fault-mode VMs. The matching xe_svm_fini() call in xe_vm_close_and_put() was updated to run unconditionally, but the error unwind path in xe_vm_create() was not. On the drm_gpuvm_resv_object_alloc() failure path, xe_svm_init() has already succeeded but xe_svm_fini() is only called when XE_VM_FLAG_FAULT_MODE is set. For non-fault-mode VMs this leaves vm->svm.gpusvm partially initialized and leaks the resources allocated by drm_gpusvm_init(). For fault-mode VMs, xe_svm_init() additionally acquires the pagemap owner via drm_pagemap_acquire_owner() and the pagemaps via xe_svm_get_pagemaps(). Those resources are released by xe_svm_close(), not xe_svm_fini(). On the same error path, xe_svm_close() is not called either, so fault-mode VMs leak the pagemap owner and pagemaps. Fix both leaks: - Call xe_svm_fini() unconditionally on the err_svm_fini path, matching the unconditional xe_svm_init() call. Move the vm->size = 0 assignment out of the conditional so the xe_vm_is_closed() assert in xe_svm_fini() (and xe_svm_close()) holds for both modes. - Call xe_svm_close() for fault-mode VMs before xe_svm_fini(), matching the ordering used in xe_vm_close_and_put(). (cherry picked from commit ca2a3587d577ba764e0fe628fb676244fc33ddd4)