drm/i915/gvt: Correct ADDR_4K/2M/1G_MASK definition

For ADDR_4K_MASK, bit[45..12] should be 1, all other bits
should be 0. The current definition wrongly set bit[46] as 1
also. This path fixes this.

v2: Add commit message, fixes and cc stable.(Zhenyu)

Fixes: 2707e444("drm/i915/gvt: vGPU graphics memory virtualization")
Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>