drm/radeon: possible buffer overflow

stable inclusion
from stable-v5.10.205
commit 7b063c93bece827fde237fae1c101bceeee4e896
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8AS5P
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.205&id=7b063c93bece827fde237fae1c101bceeee4e896



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[ Upstream commit dd05484f99d16715a88eedfca363828ef9a4c2d4 ]

Buffer 'afmt_status' of size 6 could overflow, since index 'afmt_idx' is
checked after access.

Fixes: 5cc4e5fc ("drm/radeon: Cleanup HDMI audio interrupt handling for evergreen")
Co-developed-by: Ivanov Mikhail <ivanov.mikhail1@huawei-partners.com>
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Baogen Shang <baogen.shang@windriver.com>