kernel-drm: avoid msvdx power-on to read IED register

kernel-drm: avoid msvdx power-on to read IED register

BZ: 37972

Instead to use VA_RT_FORMAT_PROTECTED to detect if IED is on.
Power-on msvdx to read IED register is not reliable,
because driver only suspend msvdx during interrupt handler.

Change-Id: I28815478ae3baee1f47682955dbf3144575e6071
Signed-off-by: Fei Jiang <fei.jiang@intel.com>
Reviewed-on: http://android.intel.com:8080/51061
Reviewed-by: Zeng, Li <li.zeng@intel.com>
Reviewed-by: Ding, Haitao <haitao.ding@intel.com>
Tested-by: Ding, Haitao <haitao.ding@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>