From commit 81bb54d15e70 ("drm/i915/gvt: add resolution definition for vGPU
type"), small type has been restricted to small resolution, so not
require larger high GM size any more. Change to smaller 384M for more
VM creation with vGPU enabled which still perform reasonable workload.
Fixes: 81bb54d15e70 ("drm/i915/gvt: add resolution definition for vGPU type") Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>