arm: dts: k3-binman: fix rcfg_yaml and pcfg_yaml labels

Fix rcfg_yaml to really point to rm-cfg.yaml and pcfg_yaml to really
point to pm-cfg.yaml which likely is the intention.

While at it also add labels for the remaining items like custmpk_pem,
dkey_pem, bcfg_yaml_sysfw, scfg_yaml_sysfw, pcfg_yaml_sysfw and
rcfg_yaml_sysfw.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Neha Malcom Francis <n-francis@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>