drm/msm: add param to retrieve # of GPU faults (global)

For KHR_robustness, userspace wants to know two things, the count of GPU
faults globally, and the count of faults attributed to a given context.
This patch providees the former, and the next patch provides the latter.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>

include/uapi/drm/msm_drm.h

@@ -75,6 +75,7 @@ struct drm_msm_timespec {
 #define MSM_PARAM_GMEM_BASE  0x06
 #define MSM_PARAM_NR_RINGS   0x07
 #define MSM_PARAM_PP_PGTABLE 0x08  /* => 1 for per-process pagetables, else 0 */
+#define MSM_PARAM_FAULTS     0x09
 
 struct drm_msm_param {
 	__u32 pipe;           /* in, MSM_PIPE_x */