drm/amd/display: Read DP_SINK_COUNT_ESI range on HPD for DP 1.4

DP 1.4 compliance now requires that registers at DP_SINK_COUNT_ESI range
(0x2002-0x2003, 0x200c-0x200f) are read instead of DP_SINK_COUNT range
(0x200-0x2005.

Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>