drm/amd/display: Fix HDMI repeater authentication

when the rxstatus split was done the index was incorrect. This
lead to HDMI repeater authentication failure for HDCP2.X So fix it

Fixes: 30216900 ("drm/amd/display: split rxstatus for hdmi and dp")
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>