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>
1 file changed