powerpc/board/t4240rdb: Enable VID support

The fuse status register provides the values from on-chip
voltage ID efuses programmed at the factory. These values
define the voltage requirements for the chip. u-boot reads
FUSESR and translates the values into the appropriate
commands to set the voltage output value of an external
voltage regulator.

Signed-off-by: Ying Zhang <b40530@freescale.com>
Reviewed-by: York Sun <york.sun@nxp.com>