drm/amdgpu: check for allocation failure in amdgpu_vkms_sw_init()

Check whether the kcalloc() fails and return -ENOMEM if it does.

Fixes: 84ec374b ("drm/amdgpu: create amdgpu_vkms (v4)")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c

@@ -482,6 +482,8 @@ static int amdgpu_vkms_sw_init(void *handle)
 		return r;
 
 	adev->amdgpu_vkms_output = kcalloc(adev->mode_info.num_crtc, sizeof(struct amdgpu_vkms_output), GFP_KERNEL);
+	if (!adev->amdgpu_vkms_output)
+		return -ENOMEM;
 
 	/* allocate crtcs, encoders, connectors */
 	for (i = 0; i < adev->mode_info.num_crtc; i++) {