drm/amd/display: Remove min_dst_y_next_start check for Z8

stable inclusion
from stable-v6.6.5
commit 7fa19a72cc79c1fa62af0818a73f47e68d57612f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8N21P

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7fa19a72cc79c1fa62af0818a73f47e68d57612f



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commit 08448812acb2ab701cd5ff7e1a1dc97f7f10260c upstream.

[Why]
Flickering occurs on DRR supported panels when engaged in DRR due to
min_dst_y_next becoming larger than the frame size itself.

[How]
In general, we should be able to enter Z8 when this is engaged but it
might be a net power loss even if the calculation wasn't bugged.

Don't support enabling Z8 during the DRR region.

Cc: stable@vger.kernel.org # 6.1+
Reviewed-by: Syed Hassan <syed.hassan@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>