[SPARC64]: Do not do TLB pre-filling any more.

In order to do it correctly on UltraSPARC-III+ and later we'd
need to add some complicated code to set the TAG access extension
register before loading the TLB.

Since this optimization gives questionable gains, it's best to
just remove it for now instead of adding the fix for Ultra-III+

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