The virtio feature bits is 64bits but the access will be split
as two times 32bits access. This patch fixes the bug which overwrites
another side 32bits, and causes feature bits are lost.
Tracked-On: #7456
Signed-off-by: Liu Long <long.liu@linux.intel.com>
Reviewed-by: Conghui <conghui.chen@intel.com>
Acked-by: Wang, Yu1 <yu1.wang@intel.com>
49426147aa