lasi: allow access to LAN MAC address registers

Firmware and qemu reads and writes the MAC address for the LASI LAN via
registers in LASI. Allow those accesses and return zero even if LASI
LAN isn't enabled to avoid HPMCs (=crashes).

Signed-off-by: Helge Deller <deller@gmx.de>

hw/misc/lasi.c

@@ -38,6 +38,7 @@ static bool lasi_chip_mem_valid(void *opaque, hwaddr addr,
     case LASI_LPT:
     case LASI_UART:
     case LASI_LAN:
+    case LASI_LAN + 12: /* LASI LAN MAC */
     case LASI_RTC:
 
     case LASI_PCR ... LASI_AMR:
@@ -78,6 +79,7 @@ static MemTxResult lasi_chip_read_with_attrs(void *opaque, hwaddr addr,
     case LASI_LPT:
     case LASI_UART:
     case LASI_LAN:
+    case LASI_LAN + 12:
         val = 0;
         break;
     case LASI_RTC: