[PATCH] [MPC52xx] Use IPB bus frequency for SOC peripherals

[PATCH] [MPC52xx] Use IPB bus frequency for SOC peripherals

The soc node of the mpc52xx needs to be loaded with the IPB bus frequency,
not the XLB frequency.

This patch depends on the previous patches for MPC52xx device tree support

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>