drm/amdkfd: fix double free device pgmap resource

Use devm_memunmap_pages instead of memunmap_pages to release pgmap
and remove pgmap from device action, to avoid double free pgmap when
unloading driver module.

Release device memory region if failed to create device memory pages
structure.
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdkfd/kfd_migrate.c

@@ -912,6 +912,8 @@ int svm_migrate_init(struct amdgpu_device *adev)
 	r = devm_memremap_pages(adev->dev, pgmap);
 	if (IS_ERR(r)) {
 		pr_err("failed to register HMM device memory\n");
+		devm_release_mem_region(adev->dev, res->start,
+					res->end - res->start + 1);
 		return PTR_ERR(r);
 	}
 
@@ -927,5 +929,9 @@ int svm_migrate_init(struct amdgpu_device *adev)
 
 void svm_migrate_fini(struct amdgpu_device *adev)
 {
-	memunmap_pages(&adev->kfd.dev->pgmap);
+	struct dev_pagemap *pgmap = &adev->kfd.dev->pgmap;
+
+	devm_memunmap_pages(adev->dev, pgmap);
+	devm_release_mem_region(adev->dev, pgmap->range.start,
+				pgmap->range.end - pgmap->range.start + 1);
 }