sparc64: Set valid bytes of misaligned no-fault loads

sparc64: Set valid bytes of misaligned no-fault loads

If a misaligned no-fault load (ldm* from ASI 0x82, primary no fault)
crosses a page boundary, and one of the pages causes an MMU miss
that cannot be resolved, then the kernel must load bytes from the
valid page into the high (or low) bytes of the destination register,
and must load zeros into the low (or high) bytes of the register.

Orabug: 25766652

Signed-off-by: Rob Gardner <rob.gardner@oracle.com>
Reviewed-by: Steve Sistare steven.sistare@oracle.com
Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>