pseries: Factor out check for out-of-bounds LIOBN

PAPR defines LIOBNs (Logical IO Bus Numbers) to be 32-bit, and we check for
values that aren't in the code for H_PUT_TCE.  This patch factors the check
into spapr_tce_find_by_liobn(), which already checks if a 32-bit LIOBN
actually exists.  This will become more important as future patches add
other hypercalls which need to look up a LIOBN.

At the same time we fix the typo in the message.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>
