hw/net/smc91c111: Use MAX_PACKET_SIZE instead of magic numbers

Now we have a constant for the maximum packet size, we can use it
to replace various hardcoded 2048 values.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250228174802.1945417-4-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/net/smc91c111.c

@@ -58,7 +58,7 @@ struct smc91c111_state {
     int tx_fifo_done_len;
     int tx_fifo_done[NUM_PACKETS];
     /* Packet buffer memory.  */
-    uint8_t data[NUM_PACKETS][2048];
+    uint8_t data[NUM_PACKETS][MAX_PACKET_SIZE];
     uint8_t int_level;
     uint8_t int_mask;
     MemoryRegion mmio;
@@ -86,7 +86,8 @@ static const VMStateDescription vmstate_smc91c111 = {
         VMSTATE_INT32_ARRAY(rx_fifo, smc91c111_state, NUM_PACKETS),
         VMSTATE_INT32(tx_fifo_done_len, smc91c111_state),
         VMSTATE_INT32_ARRAY(tx_fifo_done, smc91c111_state, NUM_PACKETS),
-        VMSTATE_BUFFER_UNSAFE(data, smc91c111_state, 0, NUM_PACKETS * 2048),
+        VMSTATE_BUFFER_UNSAFE(data, smc91c111_state, 0,
+                              NUM_PACKETS * MAX_PACKET_SIZE),
         VMSTATE_UINT8(int_level, smc91c111_state),
         VMSTATE_UINT8(int_mask, smc91c111_state),
         VMSTATE_END_OF_LIST()
@@ -773,8 +774,9 @@ static ssize_t smc91c111_receive(NetClientState *nc, const uint8_t *buf, size_t
     if (crc)
         packetsize += 4;
     /* TODO: Flag overrun and receive errors.  */
-    if (packetsize > 2048)
+    if (packetsize > MAX_PACKET_SIZE) {
         return -1;
+    }
     packetnum = smc91c111_allocate_packet(s);
     if (packetnum == 0x80)
         return -1;