drm/i915/gvt: Fix kmem_cache_create() name

According to kmem_cache_sanity_check(), spaces are not allowed in the
name of a cache and results in a kernel oops with CONFIG_DEBUG_VM.
Convert to underscores.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/execlist.c

@@ -798,7 +798,7 @@ int intel_vgpu_init_execlist(struct intel_vgpu *vgpu)
 		INIT_LIST_HEAD(&vgpu->workload_q_head[i]);
 	}
 
-	vgpu->workloads = kmem_cache_create("gvt-g vgpu workload",
+	vgpu->workloads = kmem_cache_create("gvt-g_vgpu_workload",
 			sizeof(struct intel_vgpu_workload), 0,
 			SLAB_HWCACHE_ALIGN,
 			NULL);