net/e1000/base: define max Rx jumbo frame size
net/e1000/base: define max Rx jumbo frame size

Add definition MAX_RX_JUMBO_FRAME_SIZE for igb.

All igb parts (82575 and newer) have 9.5K max jumbo frame size.

Signed-off-by: Wenzhuo Lu <58cb9036bdff9a5412edc3b9f70e105ccf59954f@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk