sparc32: Kill trap table freeing code.

Normally, srmmu uses different trap table register values to allow
determination of the cpu we're on.  All of the trap tables have
identical content, they just sit at different offsets from the first
trap table, and the offset shifted down and masked out determines
the cpu we are on.

The code tries to free them up when they aren't actually used
(don't have all 4 cpus, we're on sun4d, etc.) but that causes
problems.

For one thing it triggers false positives in the DMA debugging
code.  And fixing that up while preserving this relative offset
thing isn't trivial.

So just kill the freeing code, it costs us at most 3 pages, big
deal...

Signed-off-by: David S. Miller <davem@davemloft.net>