powerpc/booke: Merge the 32 bit e5500/e500mc cpu setup code.

Merge the 32 bit cpu setup code for e500mc/e5500 and define the
"cpu_restore" routine (for e5500/e6500) only for the 64 bit case. The
cpu_restore routine is used in the 64 bit case for setting up the secondary
cores.

Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>