MAINTAINERS: Add Intel igbvf maintainer

Add igbvf to the list of supported Intel drivers and Alex to the list of
maintainers.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -2822,10 +2822,11 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/ixp2000/
 
-INTEL ETHERNET DRIVERS (e100/e1000/e1000e/igb/ixgb/ixgbe)
+INTEL ETHERNET DRIVERS (e100/e1000/e1000e/igb/igbvf/ixgb/ixgbe)
 M:	Jeff Kirsher <jeffrey.t.kirsher@intel.com>
 M:	Jesse Brandeburg <jesse.brandeburg@intel.com>
 M:	Bruce Allan <bruce.w.allan@intel.com>
+M:	Alex Duyck <alexander.h.duyck@intel.com>
 M:	PJ Waskiewicz <peter.p.waskiewicz.jr@intel.com>
 M:	John Ronciak <john.ronciak@intel.com>
 L:	e1000-devel@lists.sourceforge.net
@@ -2835,6 +2836,7 @@ F:	drivers/net/e100.c
 F:	drivers/net/e1000/
 F:	drivers/net/e1000e/
 F:	drivers/net/igb/
+F:	drivers/net/igbvf/
 F:	drivers/net/ixgb/
 F:	drivers/net/ixgbe/