drm/i915/dp: fix the Adaptive sync Operation mode for SDP

Currently we support Adaptive sync operation mode with dynamic frame
rate, but instead the operation mode with fixed rate is set.
This was initially set correctly in the earlier version of changes but
later got changed, while defining a macro for the same.

Fixes: a5bd5991 ("drm/i915/display: Compute AS SDP parameters")
Cc: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250130051609.1796524-4-mitulkumar.ajitkumar.golani@intel.com