uboot-imx

mpc85xx: clean up the old deep sleep framework

All the boards that support deep sleep feature are converted
to deep sleep generic board interface. The old interface which
support non-generic board is not used anymore. So clean it up.

Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>