Merge upstream/main into the Spanning Tree branch

Both conflicts are the register keyword removal meeting a change of ours,
so each takes main's signature and keeps what the branch was saying:
nic_rx_packet() still returns a bool, and port_ingress_filter_get() stays
declared.

main has since put its own copy of the STP module in BANK2, so the pragma
this branch carried is now duplicated. The one with main's comment stays.

rtl837x_stp.c

@@ -6,9 +6,6 @@
 // #define REGDBG
 // #define DEBUG
 
-#pragma codeseg BANK2
-#pragma constseg BANK2
-
 #include <stdint.h>
 #include "rtl837x_common.h"
 #include "rtl837x_sfr.h"
@@ -18,6 +15,11 @@
 #include "uip.h"
 #include "machine.h"
 
+// All entry points are __banked and nothing here runs from an interrupt,
+// so the module does not need to stay in the resident bank
+#pragma codeseg BANK2
+#pragma constseg BANK2
+
 extern __code struct machine machine;
 extern __xdata uint8_t sfr_data[4];
 extern __xdata struct machine_runtime machine_detected;