drm/i915/hdcp: Remove additional timing for reading mst hdcp message

Now that we have moved back to direct reads the additional timing
is not required hence this can be removed.

--v2
-Add Fixes tag [Ankit]

Fixes: 3974f9c1 ("drm/i915/hdcp: Adjust timeout for read in DPMST Scenario")
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240223081453.1576918-10-suraj.kandpal@intel.com