drm/amd/display: Simplify bool conversion

The result of relational operation is Boolean, and the question mark
expression is redundant.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2027


Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>