powerpc/83xx: fix ULPI setup for MPC8315 processors

We must not use MPC831X_SICR[HL]_* definitions for the MPC8315 processors,
because SICR USB bits locations are not compatible with MPC8313.

This patch fixes ULPI workability on MPC8315E-RDB boards.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>