board: am43xx: Add maintainer information

am43xx_evm_ethboot/usbhost_boot_defconfig entries are
missing in MAINTAINER file. Adding entries for them.

Reported-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/board/ti/am43xx/MAINTAINERS b/board/ti/am43xx/MAINTAINERS
index d375278..3d40b17 100644
--- a/board/ti/am43xx/MAINTAINERS
+++ b/board/ti/am43xx/MAINTAINERS
@@ -5,3 +5,5 @@
 F:	include/configs/am43xx_evm.h
 F:	configs/am43xx_evm_defconfig
 F:	configs/am43xx_evm_qspiboot_defconfig
+F:	configs/am43xx_evm_ethboot_defconfig
+F:	configs/am43xx_evm_usbhost_boot_defconfig