configs: j721e_evm_r5/a72_defconfig: Enable USB Gadget related configs

Enable USB Gadget for R5 SPL, A72 SPL and A72 U-Boot to support DFU boot

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>