drm/amd/display: Correct the defined value for AMDGPU_DMUB_NOTIFICATION_MAX

stable inclusion
from stable-v6.6.50
commit 800a5ab673c4a61ca220cce177386723d91bdb37
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAYKL6

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=800a5ab673c4a61ca220cce177386723d91bdb37



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[ Upstream commit ad28d7c3d989fc5689581664653879d664da76f0 ]

[Why & How]
It actually exposes '6' types in enum dmub_notification_type. Not 5. Using smaller
number to create array dmub_callback & dmub_thread_offload has potential to access
item out of array bound. Fix it.

Reviewed-by: Jerry Zuo <jerry.zuo@amd.com>
Acked-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Wen Zhiwei <wenzhiwei@kylinos.cn>