net: mvpp2: add an entry to skip parser

This entry used when skipping the parser needed,
for example, the custom header pretended to ethernet header.

Suggested-by: Liron Himi <liron@marvell.com>
Signed-off-by: Stefan Chulski <stefanc@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>