[Delivers #156872723] Added option to enable/disable jumbo frame processing.

Configurable during device configuration. Can be enabled/disabled by setting enableJumboFrames to true or false when calling device.config. Jumbo frames are disabled by default.

Additionally, the .max_rx_pkt_len of the .rxmode of any port configuration is set based on the enabling/disabling of the jumbo frames flag. .max_rx_pkt_len is set to ETHER_MAX_LEN (1512) when not enabling jumbo frames support. When enabled, the value is set to the dev_info.max_rx_pktlen, i.e., maximum packet length supported by the device.