[dts][PATCH V1] tests/tx_preparation: modify match string of packet content

[lijuan.tu at intel.com]

On Mon, 29 Aug 2022 16:17:06 +0800, Dukai Yuan <dukaix.yuan at intel.com> wrote:
> When send 5986 byte packet, testpmd will receive 4 1460 byte packets and 1 146 byte
> packet, when use out.count("length 146"), it will retrun 5, it's worng, when use 
> out.count("length 146:"), it will retrun 1 it's right.
> 
> Signed-off-by: Dukai Yuan <dukaix.yuan at intel.com>

Acked-by: Lijuan Tu <lijuan.tu at intel.com>
Applied, thanks