[SPARC64]: Fix some SUN4V TLB handling bugs.

1) Add error return checking for TLB load hypervisor
   calls.

2) Don't fallthru to dtlb tsb miss handler from itlb tsb
   miss handler, oops.

3) On window fixups, propagate fault information to fixup
   handler correctly.

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