MAINTAINERS: add enetc_ptp driver into QorIQ PTP list

This patch to add enetc_ptp driver into QorIQ PTP list
for maintaining.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -6104,6 +6104,7 @@ FREESCALE QORIQ PTP CLOCK DRIVER
 M:	Yangbo Lu <yangbo.lu@nxp.com>
 L:	netdev@vger.kernel.org
 S:	Maintained
+F:	drivers/net/ethernet/freescale/enetc/enetc_ptp.c
 F:	drivers/ptp/ptp_qoriq.c
 F:	drivers/ptp/ptp_qoriq_debugfs.c
 F:	include/linux/fsl/ptp_qoriq.h