ptp_qoriq: support FIPER3

The FIPER3 (fixed interval period pulse generator) is supported on
DPAA2 and ENETC network controller hardware. This patch is to support
it in ptp_qoriq driver.

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