[dts] [PATCH] [PATCH]tests/Test_mtu_update:tests/Test_mtu_update start testpmd with extra parameters on melx

[Tu, Lijuan]

> Fix only tx ports are being configurated
> 
> Fix package import
> 
> melx machine need different parameters to start testpmd
> 
> Signed-off-by: David Liu <dliu at iol.unh.edu>

Applied with commit message changed