eth, miner: add RPC method to modify miner gaslimit (pre london: ceiling) (#23134)

miner/worker.go

@@ -244,6 +244,12 @@ func (w *worker) setEtherbase(addr common.Address) {
 	w.coinbase = addr
 }
 
+func (w *worker) setGasCeil(ceil uint64) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	w.config.GasCeil = ceil
+}
+
 // setExtra sets the content used to initialize the block extra field.
 func (w *worker) setExtra(extra []byte) {
 	w.mu.Lock()