crnlib: fix CodeQL report cpp/comparison-with-wider-type

Author: illwieckz

crnlib/crn_comp.cpp

@@ -890,7 +890,7 @@ static void remap_alpha_endpoints(uint16* remapping, const optimize_alpha_params
     const optimize_alpha_params::unpacked_endpoint& e_back = unpacked_endpoints[chosen.back()];
     uint16 selected_index = 0;
     uint64 best_value = 0, selected_similarity_front = 0, selected_similarity_back = 0;
-    for (uint16 i = 0; i < remaining.size(); i++) {
+    for (size_t i = 0; i < remaining.size(); i++) {
       uint remaining_index = remaining[i];
       const optimize_alpha_params::unpacked_endpoint& e_remaining = unpacked_endpoints[remaining_index];
       uint error_front = math::square(e_remaining.low - e_front.low) + math::square(e_remaining.high - e_front.high);
@@ -919,7 +919,7 @@ static void remap_alpha_endpoints(uint16* remapping, const optimize_alpha_params
       chosen.push_back(selected);
     }
     remaining.erase(remaining.begin() + selected_index);
-    for (uint16 i = 0; i < remaining.size(); i++)
+    for (size_t i = 0; i < remaining.size(); i++)
       total_frequency[remaining[i]] += frequency[remaining[i]];
   }
   for (uint16 i = 0; i < n; i++)