zynqmp: Add avnet_ultra96_rev1_defconfig to the lits of boards

Signed-off-by: Tom Rini <trini@konsulko.com>

board/xilinx/zynqmp/MAINTAINERS

@@ -5,3 +5,4 @@ F:	arch/arm/dts/zynqmp-*
 F:	board/xilinx/zynqmp/
 F:	include/configs/xilinx_zynqmp*
 F:	configs/xilinx_zynqmp*
+F:	configs/avnet_ultra96_rev1_defconfig