powerpc/mpc85xx: Add ranges to etsec2 nodes

Commit 746c9e9f92dd "of/base: Fix PowerPC address parsing hack" limited
the applicability of the workaround whereby a missing ranges is treated
as an empty ranges.  This workaround was hiding a bug in the etsec2
device tree nodes, which have children with reg, but did not have
ranges.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Reported-by: Alexander Graf <agraf@suse.de>