drm/amd/display: Change i2c speed for hdcp

[why]
HDCP 1.4 failed on SL8800 SW w/a test driver use.

[how]
slower down the HW i2c speed when used by HW i2c.
Tested-by: Daniel Wheeler <Daniel.Wheeler@amd.com>
Reviewed-by: Aurabindo Pillai <Aurabindo.Pillai@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn316/dcn316_resource.c

@@ -1776,7 +1776,7 @@ static bool dcn316_resource_construct(
 	pool->base.mpcc_count = pool->base.res_cap->num_timing_generator;
 	dc->caps.max_downscale_ratio = 600;
 	dc->caps.i2c_speed_in_khz = 100;
-	dc->caps.i2c_speed_in_khz_hdcp = 100;
+	dc->caps.i2c_speed_in_khz_hdcp = 5; /*1.5 w/a applied by default*/
 	dc->caps.max_cursor_size = 256;
 	dc->caps.min_horizontal_blanking_period = 80;
 	dc->caps.dmdata_alloc_size = 2048;