drm/msm/a6xx: fix a potential overflow issue

It's allocating an array of a6xx_gpu_state_obj structure rathor than
its pointers.

This patch fix it.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c

@@ -875,7 +875,7 @@ static void a6xx_get_indexed_registers(struct msm_gpu *gpu,
 	int i;
 
 	a6xx_state->indexed_regs = state_kcalloc(a6xx_state, count,
-		sizeof(a6xx_state->indexed_regs));
+		sizeof(*a6xx_state->indexed_regs));
 	if (!a6xx_state->indexed_regs)
 		return;