drm/msm/a6xx: avoid shadow NULL reference in failure path

stable inclusion
from stable-v5.10.44
commit fd681a8c7ac8f649a0718f6cbf2fe75d0587c9a2
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=472
CVE: NA

-------------------------------------------------

commit ce86c239 upstream.

If a6xx_hw_init() fails before creating the shadow_bo, the a6xx_pm_suspend
code referencing it will crash. Change the condition to one that avoids
this problem (note: creation of shadow_bo is behind this same condition)

Fixes: e8b0b994 ("drm/msm/a6xx: Clear shadow on suspend")
Signed-off-by: NJonathan Marek <jonathan@marek.ca>
Reviewed-by: NAkhil P Oommen <akhilpo@codeaurora.org>
Link: https://lore.kernel.org/r/20210513171431.18632-6-jonathan@marek.caSigned-off-by: NRob Clark <robdclark@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Nlzb <zbliancs@qq.com>
Reviewed-by: NJian Cheng <cj.chengjian@huawei.com>
Signed-off-by: NWang ShaoBo <bobo.shaobowang@huawei.com>

drivers/gpu/drm/msm/adreno/a6xx_gpu.c

@@ -1055,7 +1055,7 @@ static int a6xx_pm_suspend(struct msm_gpu *gpu)
 	if (ret)
 		return ret;
 
-	if (adreno_gpu->base.hw_apriv || a6xx_gpu->has_whereami)
+	if (a6xx_gpu->shadow_bo)
 		for (i = 0; i < gpu->nr_rings; i++)
 			a6xx_gpu->shadow[i] = 0;