mapper-related updates and fixes (#491)

* m116: Fix support for Huang-2 chip

* Provide 8K CHR ram if no CHR rom/ram is provided due to bad headers

* m15: Implement CHR write-protect

* Update Namco 106

- Cleanup save state struct
- Implement nametable mirroring
- fix sound issue (fceux)

Co-authored-by: negativeExponent <negativeExponent@users.noreply.github.com>

src/boards/fk23c.c

@@ -41,7 +41,6 @@
 */
 
 #include "mapinc.h"
-#include "../ines.h"
 
 static uint8 *WRAM            = NULL;
 static uint8 *CHRRAM          = NULL;
@@ -64,6 +63,9 @@ static uint8 jncota523        = 0; /* Jncota board with unusual wiring that turn
 static uint8 dipsw_enable     = 0; /* Change the address mask on every reset? */
 static uint8 after_power      = 0; /* Used for detecting whether a DIP switch is used or not (see above) */
 
+extern uint32 ROM_size;
+extern uint32 VROM_size;
+
 static SFORMAT StateRegs[] = {
    { fk23_regs,               8, "EXPR" },
    { mmc3_regs,              12, "M3RG" },