ARM: dts: imx: change iim node name on i.MX SoCs

Change IIM node name from iim to efuse to be compliant
with yaml schema, it requires the nodename to be one of
"eeprom|efuse|nvram".

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>