drm/amd/display: Remove the unused variable dppclk_delay_subtotal

drm/amd/display: Remove the unused variable dppclk_delay_subtotal

Variable dppclk_delay_subtotal is not effectively used, so delete it.

drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn314/display_rq_dlg_calc_314.c:1004:15: warning: variable 'dppclk_delay_subtotal' set but not used.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4584
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>