MAINTAINERS: add myself as maintainer for enetc

I would like to be copied on new patches submitted on this driver.
I am relatively familiar with the code, having practically maintained
it for a while.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: vladimiroltean

MAINTAINERS

@@ -8159,6 +8159,7 @@ F:	include/linux/spi/spi-fsl-dspi.h
 
 FREESCALE ENETC ETHERNET DRIVERS
 M:	Claudiu Manoil <claudiu.manoil@nxp.com>
+M:	Vladimir Oltean <vladimir.oltean@nxp.com>
 L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/ethernet/freescale/enetc/