Gfx-display: correct sleep function usage for DVx

Gfx-display: correct sleep function usage for DVx

BZ: 36765

use usleep_range instead of mdelay and msleep for short time delay.

Change-Id: Ic9b1bb246e555d8817d87f4d25347bcf0a9f7049
Signed-off-by: Geng Xiujun <xiujun.geng@intel.com>
Reviewed-on: http://android.intel.com:8080/49126
Reviewed-by: Hogander, Jouni <jouni.hogander@intel.com>
Reviewed-by: Xu, Randy <randy.xu@intel.com>
Tested-by: Tong, BoX <box.tong@intel.com>
Reviewed-by: Imberton, Guilhem <guilhem.imberton@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>