drm/amd/display: fix cond_no_effect.cocci warnings

This was found by coccicheck:
./drivers/gpu/drm/amd/display/dc/core/dc_resource.c, 2516, 7-9, WARNING
possible condition with no effect (if == else)

hdmi_info.bits.YQ0_YQ1 is always YYC_QUANTIZATION_LIMITED_RANGE.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Ye Guojin <ye.guojin@zte.com.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>