board: ti: j748s4: Add board config yaml files

Add board-cfg, rm-cfg, pm-cfg, sec-cfg, tifs-rm-cfg yaml for buidling
u-boot sysfw data.

[ added board specific yaml files for binman ]
Signed-off-by: Neha Malcom Francis <n-francis@ti.com>
Signed-off-by: Apurva Nandan <a-nandan@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> # AM69-SK