drm/i915/dp: Iterate DSC BPP from high to low on all platforms

Commit 1c56e9a ("drm/i915/dp: Get optimal link config to have best
compressed bpp") tries to find the best compressed bpp for the
link. However, it iterates from max to min bpp on display 13+, and from
min to max on other platforms. This presumably leads to minimum
compressed bpp always being chosen on display 11-12.

Iterate from high to low on all platforms to actually use the best
possible compressed bpp.

Fixes: 1c56e9a ("drm/i915/dp: Get optimal link config to have best compressed bpp")
Cc: Ankit Nautiyal <[email protected]>
Cc: Imre Deak <[email protected]>
Cc: <[email protected]> # v6.7+
Reviewed-by: Imre Deak <[email protected]>
Reviewed-by: Ankit Nautiyal <[email protected]>
Signed-off-by: Jani Nikula <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/3bba67923cbcd13a59d26ef5fa4bb042b13c8a9b.1738327620.git.jani.nikula@intel.com
(cherry picked from commit 56b0337)
Signed-off-by: Rodrigo Vivi <[email protected]>

Author: jnikula

drivers/gpu/drm/i915/display/intel_dp.c

@@ -2072,11 +2072,10 @@ icl_dsc_compute_link_config(struct intel_dp *intel_dp,
 	/* Compressed BPP should be less than the Input DSC bpp */
 	dsc_max_bpp = min(dsc_max_bpp, pipe_bpp - 1);
 
-	for (i = 0; i < ARRAY_SIZE(valid_dsc_bpp); i++) {
-		if (valid_dsc_bpp[i] < dsc_min_bpp)
+	for (i = ARRAY_SIZE(valid_dsc_bpp) - 1; i >= 0; i--) {
+		if (valid_dsc_bpp[i] < dsc_min_bpp ||
+		    valid_dsc_bpp[i] > dsc_max_bpp)
 			continue;
-		if (valid_dsc_bpp[i] > dsc_max_bpp)
-			break;
 
 		ret = dsc_compute_link_config(intel_dp,
 					      pipe_config,