Merge pull request #4964 from tonhuisman/feature/Build-allow-feature_servo-for-custom-limit_build_size

[Build] Allow FEATURE_SERVO for Custom builds with LIMIT_BUILD_SIZE set

Author: TD-er

src/src/CustomBuild/define_plugin_sets.h

@@ -2568,10 +2568,12 @@ To create/register a plugin, you have to :
   #endif
   #define FEATURE_SETTINGS_ARCHIVE  0
 
+  #ifndef PLUGIN_BUILD_CUSTOM
   #ifdef FEATURE_SERVO
     #undef FEATURE_SERVO
   #endif
   #define FEATURE_SERVO 0
+  #endif
   #ifdef FEATURE_RTTTL
     #undef FEATURE_RTTTL
   #endif