drm/amd/display: Reduce default backlight min from 5 nits to 1 nits

stable inclusion
from stable-v6.6.5
commit 86cd446a7727f92db999b55c66e9a59cf7a0545a
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=86cd446a7727f92db999b55c66e9a59cf7a0545a



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[ Upstream commit 5edb7cdff85af8f8c5fda5b88310535ab823f663 ]

[Why & How]
Currently set_default_brightness_aux function uses 5 nits as lower limit
to check for valid default_backlight setting. However some newer panels
can support even lower default settings

Reviewed-by: Agustin Gutierrez <agustin.gutierrez@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Swapnil Patel <swapnil.patel@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Stable-dep-of: d9e865826c20 ("drm/amd/display: Simplify brightness initialization")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>