drm/amd/amdgpu: fix performance drop when VRAM pressure

When VRAM pressue and trigger huge evictions there is performance drop,
this patch fix it.

Signed-off-by: Roger.He <[e-mail]>
Reviewed-by: Christian König <[e-mail]>
Reviewed-by: Alex Deucher <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

···
 	if (unlikely(r != 0))
 		return r;
 
-	bo->tbo.priority = ilog2(bo->tbo.num_pages);
 	if (kernel)
-		bo->tbo.priority *= 2;
-	bo->tbo.priority = min(bo->tbo.priority, (unsigned)(TTM_MAX_BO_PRIORITY - 1));
+		bo->tbo.priority = 1;
 
 	if (flags & AMDGPU_GEM_CREATE_VRAM_CLEARED &&
 	    bo->tbo.mem.placement & TTM_PL_FLAG_VRAM) {