examples/l3fwd: fix option parsing
examples/l3fwd: fix option parsing

Fix minor, and non critical, copy and paste error in strncmp() of eth-dest
commandline argument.

Fixes: bd785f6f6791 ("examples/l3fwd: make destination mac address configurable")

Signed-off-by: John McNamara <af31595c36a4239b9676e9b3a777d3e2f15a6c4d@intel.com>
Acked-by: Andrey Chilikin <e7d64155883734f893a62d2f3554768227530801@intel.com>

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