net: mscc: ocelot: avoid incorrect consuming in skbs list

Break the matching loop when find the matching skb for TX timestamp.
This is to avoid consuming more skbs incorrectly. The timestamp ID
is from 0 to 3 while the FIFO could support 128 timestamps at most.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>