sparc32: Restore SMP build and rectify sun4m NMI when non-SMP.

The non-SMP sun4m NMI handler was still accessing SUN4C registers.

Fix that and share the sun4m NMI trap code between SMP and non-SMP
cases.

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