igt@kms_dither@fb-8bpc-vs-panel-6bpc@* - skip - Test requirement: !ret, don't support 6-bpc

https://intel-gfx-ci.01.org/tree/intel-xe/xe-946-b7ead5c90db25002638773b1a9289220e6a36b4d/re-adlp-pub6/igt@kms_dither@fb-8bpc-vs-panel-6bpc@pipe-a-hdmi-a-1.html

Out	
Starting dynamic subtest: pipe-A-HDMI-A-1
Dithering test execution on HDMI-A-1 PIPE_A
Test requirement not met in function test_dithering, file ../../../usr/src/igt-gpu-tools/tests/kms_dither.c:180:
Test requirement: !ret
HDMI-A-1 don't support 6-bpc
Dynamic subtest pipe-A-HDMI-A-1: SKIP (0.003s)