octeontx2-pf: Increase the size of dmac filter flows

CN10kb supports large number of dmac filter flows to be
inserted. Increase the field size to accommodate the same

Fixes: b747923a ("octeontx2-af: Exact match support")
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>