board: ti: am64x: Update MAINTAINERS

Move maintainership of TI AM64x boards to Vignesh.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
diff --git a/board/ti/am64x/MAINTAINERS b/board/ti/am64x/MAINTAINERS
index eaca2b8..78a21d6 100644
--- a/board/ti/am64x/MAINTAINERS
+++ b/board/ti/am64x/MAINTAINERS
@@ -1,5 +1,5 @@
 AM64x BOARD
-M:	Dave Gerlach <d-gerlach@ti.com>
+M:	Vignesh Raghavendra <vigneshr@ti.com>
 M:	Tom Rini <trini@konsulko.com>
 S:	Maintained
 F:	board/ti/am64x/