vie_read/write_bytereg call vm_get/set_register to get/set byteregs.
We have make vm_get/set_register as non-failed function in previous patch.
So, this patch make the vie_read/write_bytereg as non-failed function too.
Signed-off-by: Kaige Fu <kaige.fu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>