powerpc/85xx: sbc8548 - fixup of PCI-e related DTS fields

The PCI-e addressing was originally patterned of the MPC8548CDS
which has PCI1, PCI2, and PCI-e.  Since this board only has
PCI1 and PCI-e, it makes more sense to be similar to the MPC8568MDS
board.  This does that by cutting the PCI/PCI-e I/O sizes from
16MB to 8MB and pulling the PCI-e I/O range back to 0xe280_0000
(the hole where PCI2 I/O would have been).

This also fixes a typo where an extra zero made an 8MB range a 128MB
range, removes the hole left by PCI2 from the aliases, and sets the
clocks to match the oscillators that are actually on the board.

With accompanying u-boot updates, PCI-e has been validated with
both a sky2 card (1148:9e00) and an e1000 card (8086:108b).

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>