drm/amdgpu: mmVM_L2_CNTL3 register not initialized correctly

stable inclusion
from stable-v5.10.143
commit dfb27648eea5a5729b544198c1867887fe9420c6
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0U6

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dfb27648eea5a5729b544198c1867887fe9420c6



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[ Upstream commit b8983d42 ]

The mmVM_L2_CNTL3 register is not assigned an initial value

Signed-off-by: Qu Huang <jinsdb@126.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com>