MINOR: Remove unused fields in KafkaConfig (apache#19481)

This is a follow-up clean of apache#19387   Since we no longer access the log
cleaner config from `KafkaConfig`, we should remove these unused fields.

Reviewers: Ken Huang <[email protected]>, Chia-Ping Tsai
<[email protected]>

Author: frankvicky

core/src/main/scala/kafka/server/KafkaConfig.scala

@@ -333,13 +333,9 @@ class KafkaConfig private(doLog: Boolean, val props: util.Map[_, _])
 
   def logRetentionBytes = getLong(ServerLogConfigs.LOG_RETENTION_BYTES_CONFIG)
   def logCleanerDedupeBufferSize = getLong(CleanerConfig.LOG_CLEANER_DEDUPE_BUFFER_SIZE_PROP)
-  def logCleanerDedupeBufferLoadFactor = getDouble(CleanerConfig.LOG_CLEANER_DEDUPE_BUFFER_LOAD_FACTOR_PROP)
-  def logCleanerIoBufferSize = getInt(CleanerConfig.LOG_CLEANER_IO_BUFFER_SIZE_PROP)
-  def logCleanerIoMaxBytesPerSecond = getDouble(CleanerConfig.LOG_CLEANER_IO_MAX_BYTES_PER_SECOND_PROP)
   def logCleanerDeleteRetentionMs = getLong(CleanerConfig.LOG_CLEANER_DELETE_RETENTION_MS_PROP)
   def logCleanerMinCompactionLagMs = getLong(CleanerConfig.LOG_CLEANER_MIN_COMPACTION_LAG_MS_PROP)
   def logCleanerMaxCompactionLagMs = getLong(CleanerConfig.LOG_CLEANER_MAX_COMPACTION_LAG_MS_PROP)
-  def logCleanerBackoffMs = getLong(CleanerConfig.LOG_CLEANER_BACKOFF_MS_PROP)
   def logCleanerMinCleanRatio = getDouble(CleanerConfig.LOG_CLEANER_MIN_CLEAN_RATIO_PROP)
   def logIndexSizeMaxBytes = getInt(ServerLogConfigs.LOG_INDEX_SIZE_MAX_BYTES_CONFIG)
   def logIndexIntervalBytes = getInt(ServerLogConfigs.LOG_INDEX_INTERVAL_BYTES_CONFIG)