drm/i915/gvt: Disable primary/sprite/cursor plane at virtual display initialization

Much error exist in host dmesg during guest boot up with loca display
enabled.
gvt: vgpu 1: invalid range gmadr 0x0 size 0x0

This error happens when qemu get dmabuf info in case that the virtual
display plane is enabled but its base address is an invalid 0, such
case may be true before guest enable its plane. At this moment, its
state is copied from host where the plane may be enabled.

This patch disable primary/sprite/cursor plane at virtual display
initialization, so intel_vgpu_decode_primary/cursor/sprite could
return early as plane is disabled, then plane base check is skipped and
error message disapper.

Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>